2024 |
Yao, Ruixiao; Chi, Sungjae; Mukherjee, Biswaroop; Shaffer, Airlia; Zwierlein, Martin; Fletcher, Richard J Observation of chiral edge transport in a rapidly rotating quantum gas Journal Article In: Nature, vol. 20, iss. 11, pp. 1726–1731, 2024. @article{ryao2024, The frictionless directional propagation of particles at the boundary of topological materials is a striking transport phenomenon. These chiral edge modes lie at the heart of the integer and fractional quantum Hall effects, and their robustness against noise and disorder reflects the quantization of Hall conductivity in these systems. Despite their importance, the controllable injection of edge modes, and direct imaging of their propagation, structure and dynamics, remains challenging. Here we demonstrate the distillation of chiral edge modes in a rapidly rotating bosonic superfluid confined by an optical boundary. By tuning the wall sharpness, we reveal the smooth crossover between soft wall behaviour in which the propagation speed is proportional to wall steepness and the hard wall regime that exhibits chiral free particles. From the skipping motion of atoms along the boundary we infer the energy gap between the ground and first excited edge bands, and reveal its evolution from the bulk Landau level splitting for a soft boundary to the hard wall limit. Finally, we demonstrate the robustness of edge propagation against disorder by projecting an optical obstacle that is static in the rotating frame. |
Dolgirev, Pavel E; Seetharam, Kushal; Kanász-Nagy, Márton; Robens, Carsten; Yan, Zoe Z; Zwierlein, Martin; Demler, Eugene Accelerating analysis of Boltzmann equations using Gaussian mixture models: Application to quantum Bose-Fermi mixtures Journal Article In: Physical Review Research, vol. 6, iss. 3, 2024. @article{pdolgirev2024, The Boltzmann equation is a powerful theoretical tool for modeling the collective dynamics of quantum many-body systems subject to external perturbations. Analysis of the equation gives access to linear response properties including collective modes and transport coefficients, but often proves intractable due to computational costs associated with multidimensional integrals describing collision processes. Here, we present a method to resolve this bottleneck, enabling the study of a broad class of many-body systems that appear in fundamental science contexts and technological applications. Specifically, we demonstrate that a Gaussian mixture model can accurately represent equilibrium distribution functions, thereby allowing efficient evaluation of collision integrals. Inspired by cold atom experiments, we apply this method to investigate the collective behavior of a quantum Bose-Fermi mixture of cold atoms in a cigar-shaped trap, a system that is particularly challenging to analyze. We focus on monopole and quadrupole collective modes above the Bose-Einstein transition temperature, and find a rich phenomenology that spans interference effects between bosonic and fermionic collective modes, dampening of these modes, and the emergence of hydrodynamics in various parameter regimes. These effects are readily verifiable experimentally. |
Yan, Zoe Z; Ni, Yiqi; Chuang, Alexander; Dolgirev, Pavel E; Seetharam, Kushal; Demler, Eugene; Robens, Carsten; Zwierlein, Martin Collective flow of fermionic impurities immersed in a Bose–Einstein condensate Journal Article In: Nature Physics, vol. 20, pp. 1395–1400, 2024. @article{zzyan2024, Interacting mixtures of bosons and fermions are ubiquitous in nature. They form the backbone of the standard model of physics, provide a framework for understanding quantum materials and are of technological importance in helium dilution refrigerators. However, the description of their coupled thermodynamics and collective behaviour is challenging. Bose–Fermi mixtures of ultracold atoms provide a platform to investigate their properties in a highly controllable environment, where the species concentration and interaction strength can be tuned at will. Here we characterize the collective oscillations of spin-polarized fermionic impurities immersed in a Bose–Einstein condensate as a function of the interaction strength and temperature. For strong interactions, the Fermi gas perfectly mimics the superfluid hydrodynamic modes of the condensate, from low-energy quadrupole modes to high-order Faraday excitations. With an increasing number of bosonic thermal excitations, the dynamics of the impurities cross over from the collisionless to the hydrodynamic regime, reminiscent of the emergence of hydrodynamics in two-dimensional electron fluids. |
Yan, Zhenjie; Patel, Parth B; Mukherjee, Biswaroop; Vale, Chris J; Fletcher, Richard J; Zwierlein, Martin Thermography of the superfluid transition in a strongly interacting Fermi gas Journal Article In: Science, vol. 383, iss. 6683, pp. 629–633, 2024. @article{zyan2024, Heat transport can serve as a fingerprint identifying different states of matter. In a normal liquid, a hotspot diffuses, whereas in a superfluid, heat propagates as a wave called “second sound.” Direct imaging of heat transport is challenging, and one usually resorts to detecting secondary effects. In this study, we establish thermography of a strongly interacting atomic Fermi gas, whose radio-frequency spectrum provides spatially resolved thermometry with subnanokelvin resolution. The superfluid phase transition was directly observed as the sudden change from thermal diffusion to second-sound propagation and is accompanied by a peak in the second-sound diffusivity. This method yields the full heat and density response of the strongly interacting Fermi gas and therefore all defining properties of Landau’s two-fluid hydrodynamics. |
2023 |
Hartke, Thomas; Oreg, Botond; Turnbaugh, Carter; Jia, Ningyuan; Zwierlein, Martin Direct observation of nonlocal fermion pairing in an attractive Fermi-Hubbard gas Journal Article In: Science, vol. 381, iss. 6653, pp. 82–86, 2023. @article{thartke2023, The Hubbard model of attractively interacting fermions provides a paradigmatic setting for fermion pairing. It features a crossover between Bose-Einstein condensation of tightly bound pairs and Bardeen-Cooper-Schrieffer superfluidity of long-range Cooper pairs, and a “pseudo-gap” region where pairs form above the superfluid critical temperature. We directly observe the nonlocal nature of fermion pairing in a Hubbard lattice gas, using spin- and density-resolved imaging of 1000 fermionic potassium-40 atoms under a bilayer microscope. Complete fermion pairing is revealed by the vanishing of global spin fluctuations with increasing attraction. In the strongly correlated regime, the fermion pair size is found to be on the order of the average interparticle spacing. Our study informs theories of pseudo-gap behavior in strongly correlated fermion systems. |
2022 |
Mukherjee, Biswaroop; Shaffer, Airlia; Patel, Parth B.; Yan, Zhenjie; Wilson, Cedric C.; Crépel, Valentin; Fletcher, Richard J.; Zwierlein, Martin Crystallization of bosonic quantum Hall states in a rotating quantum gas Journal Article In: Nature, vol. 601, pp. 58–62, 2022. @article{Mukherjee2022, The dominance of interactions over kinetic energy lies at the heart of strongly correlated quantum matter, from fractional quantum Hall liquids1, to atoms in optical lattices2 and twisted bilayer graphene3. Crystalline phases often compete with correlated quantum liquids, and transitions between them occur when the energy cost of forming a density wave approaches zero. A prime example occurs for electrons in high-strength magnetic fields, where the instability of quantum Hall liquids towards a Wigner crystal is heralded by a roton-like softening of density modulations at the magnetic length. Remarkably, interacting bosons in a gauge field are also expected to form analogous liquid and crystalline states. However, combining interactions with strong synthetic magnetic fields has been a challenge for experiments on bosonic quantum gases. Here we study the purely interaction-driven dynamics of a Landau gauge Bose--Einstein condensate in and near the lowest Landau level. We observe a spontaneous crystallization driven by condensation of magneto-rotons, excitations visible as density modulations at the magnetic length. Increasing the cloud density smoothly connects this behaviour to a quantum version of the Kelvin--Helmholtz hydrodynamic instability, driven by the sheared internal flow profile of the rapidly rotating condensate. At long times the condensate self-organizes into a persistent array of droplets separated by vortex streets, which are stabilized by a balance of interactions and effective magnetic forces. |
Hartke, Thomas; Oreg, Botond; Jia, Ningyuan; Zwierlein, Martin Quantum register of fermion pairs Journal Article In: Nature, vol. 601, pp. 537–541, 2022. @article{Hartke2022, Quantum control of motion is central for modern atomic clocks1 and interferometers2. It enables protocols to process and distribute quantum information3,4, and allows the probing of entanglement in correlated states of matter5. However, the motional coherence of individual particles can be fragile to maintain, as external degrees of freedom couple strongly to the environment. Systems in nature with robust motional coherence instead often involve pairs of particles, from the electrons in helium, to atom pairs6, molecules7 and Cooper pairs. Here we demonstrate long-lived motional coherence and entanglement of pairs of fermionic atoms in an optical lattice array. The common and relative motion of each pair realize a robust qubit, protected by exchange symmetry. The energy difference between the two motional states is set by the atomic recoil energy, is dependent on only the mass and the lattice wavelength, and is insensitive to the noise of the confining potential. We observe quantum coherence beyond ten seconds. Modulation of the interactions between the atoms provides universal control of the motional qubit. The methods presented here will enable coherently programmable quantum simulators of many-fermion systems8, precision metrology based on atom pairs and molecules9,10 and, by implementing further advances11--13, digital quantum computation using fermion pairs14. |
Karman, Tijs; Yan, Zoe Z.; Zwierlein, Martin Resonant and first-order dipolar interactions between ultracold $upSigma$1 molecules in static and microwave electric fields Journal Article In: Phys. Rev. A, vol. 105, no. 1, 2022. @article{Karman_2022, |
2021 |
Hertkorn, J.; Schmidt, J. -N.; Guo, M.; Böttcher, F.; Ng, K. S. H.; Graham, S. D.; Uerlings, P.; Büchler, H. P.; Langen, T.; Zwierlein, M.; Pfau, T. Supersolidity in Two-Dimensional Trapped Dipolar Droplet Arrays Journal Article In: Phys. Rev. Lett., vol. 127, no. 15, 2021. @article{Hertkorn_2021c, |
Hertkorn, J.; Schmidt, J. -N.; Guo, M.; Böttcher, F.; Ng, K. S. H.; Graham, S. D.; Uerlings, P.; Langen, T.; Zwierlein, M.; Pfau, T. Pattern formation in quantum ferrofluids: From supersolids to superglasses Journal Article In: Phys. Rev. Research, vol. 3, no. 3, 2021. @article{Hertkorn_2021, |
Fletcher, Richard J.; Shaffer, Airlia; Wilson, Cedric C.; Patel, Parth B.; Yan, Zhenjie; Crépel, Valentin; Mukherjee, Biswaroop; Zwierlein, Martin W. Geometric squeezing into the lowest Landau level Journal Article In: Science, vol. 372, no. 6548, pp. 1318–1322, 2021. @article{Fletcher_2021, |
Schmidt, J. -N.; Hertkorn, J.; Guo, M.; Böttcher, F.; Schmidt, M.; Ng, K. S. H.; Graham, S. D.; Langen, T.; Zwierlein, M.; Pfau, T. Roton Excitations in an Oblate Dipolar Quantum Gas Journal Article In: Phys. Rev. Lett., vol. 126, no. 19, 2021. @article{Schmidt_2021, |
Hertkorn, J.; Schmidt, J. -N.; Böttcher, F.; Guo, M.; Schmidt, M.; Ng, K. S. H.; Graham, S. D.; Büchler, H. P.; Langen, T.; Zwierlein, M.; Pfau, T. Density Fluctuations across the Superfluid-Supersolid Phase Transition in a Dipolar Quantum Gas Journal Article In: Phys. Rev. X, vol. 11, no. 1, 2021. @article{Hertkorn_2021b, |
Altman, Ehud; Brown, Kenneth R.; Carleo, Giuseppe; Carr, Lincoln D.; Demler, Eugene; Chin, Cheng; DeMarco, Brian; Economou, Sophia E.; Eriksson, Mark A.; Fu, Kai-Mei C.; Greiner, Markus; Hazzard, Kaden R. A.; Hulet, Randall G.; Kollár, Alicia J.; Lev, Benjamin L.; Lukin, Mikhail D.; Ma, Ruichao; Mi, Xiao; Misra, Shashank; Monroe, Christopher; Murch, Kater; Nazario, Zaira; Ni, Kang-Kuen; Potter, Andrew C.; Roushan, Pedram; Saffman, Mark; Schleier-Smith, Monika; Siddiqi, Irfan; Simmonds, Raymond; Singh, Meenakshi; Spielman, I. B.; Temme, Kristan; Weiss, David S.; Vučković, Jelena; Vuletić, Vladan; Ye, Jun; Zwierlein, Martin Quantum Simulators: Architectures and Opportunities Journal Article In: PRX Quantum Quantum, vol. 2, no. 1, 2021. @article{Altman_2021, |
2020 |
Patel, Parth B; Yan, Zhenjie; Mukherjee, Biswaroop; Fletcher, Richard J; Struck, Julian; Zwierlein, Martin Universal Sound Diffusion in a Strongly Interacting Fermi Gas Journal Article In: Science, vol. 370, pp. 1222-1226, 2020. @article{Patel2020, |
Hartke, Thomas; Oreg, Botond; Jia, Ningyuan; Zwierlein, Martin Doublon-Hole Correlations and Fluctuation Thermometry in a Fermi-Hubbard Gas Journal Article In: Phys. Rev. Lett., vol. 125, no. 11, 2020. @article{Hartke_2020, |
Yan, Zoe Z; Ni, Yiqi; Robens, Carsten; Zwierlein, Martin Bose polarons near quantum criticality Journal Article In: Science, vol. 368, pp. 190-194, 2020. @article{Yan2019a, The emergence of quasiparticles in strongly interacting matter represents one of the cornerstones of modern physics. However, when different phases of matter compete near a quantum critical point, the very existence of quasiparticles comes under question. Here we create Bose polarons near quantum criticality by immersing atomic impurities in a Bose-Einstein condensate (BEC) with near-resonant interactions. Using locally-resolved radiofrequency spectroscopy, we probe the energy, spectral width, and short-range correlations of the impurities as a function of temperature. Far below the superfluid critical temperature, the impurities form well-defined quasiparticles. However, their inverse lifetime, given by their spectral width, is observed to increase linearly with temperature, a hallmark of quantum critical behavior. Close to the BEC critical temperature, the spectral width exceeds the binding energy of the impurities, signaling a breakdown of the quasiparticle picture near quantum criticality. |
Yan, Zoe Z; Park, Jee Woo; Ni, Yiqi; Loh, Huanqian; Will, Sebastian; Karman, Tijs; Zwierlein, Martin Resonant dipolar collisions of ultracold molecules induced by microwave dressing Journal Article In: Phys. Rev. Lett., vol. 125, pp. 063401, 2020. @article{yan2020resonant, |
2019 |
Christianen, Arthur; Zwierlein, Martin W; Groenenboom, Gerrit C; Karman, Tijs Photoinduced Two-Body Loss of Ultracold Molecules Journal Article In: Physical Review Letters, vol. 123, no. 12, 2019, ISSN: 10797114. @article{Christianen2019, The lifetime of nonreactive ultracold bialkali gases was conjectured to be limited by sticky collisions amplifying three-body loss. We show that the sticking times were previously overestimated and do not support this hypothesis. We find that electronic excitation of NaK+NaK collision complexes by the trapping laser leads to the experimentally observed two-body loss. We calculate the excitation rate with a quasiclassical, statistical model employing ab initio potentials and transition dipole moments. Using longer laser wavelengths or repulsive box potentials may suppress the losses. |
Mukherjee, Biswaroop; Patel, Parth B; Yan, Zhenjie; Fletcher, Richard J; Struck, Julian; Zwierlein, Martin W Spectral Response and Contact of the Unitary Fermi Gas Journal Article In: Physical Review Letters, vol. 122, no. 20, pp. 203402, 2019. @article{Mukherjee2019, |
Yan, Zhenjie; Patel, Parth B; Mukherjee, Biswaroop; Fletcher, Richard J; Struck, Julian; Zwierlein, Martin W Boiling a Unitary Fermi Liquid Journal Article In: Physical Review Letters, vol. 122, no. 9, 2019, ISSN: 10797114. @article{Yan2019, We study the thermal evolution of a highly spin-imbalanced, homogeneous Fermi gas with unitarity limited interactions, from a Fermi liquid of polarons at low temperatures to a classical Boltzmann gas at high temperatures. Radio-frequency spectroscopy gives access to the energy, lifetime, and short-range correlations of Fermi polarons at low temperatures $T$. In this regime, we observe a characteristic $T^2$ dependence of the spectral width, corresponding to the quasiparticle decay rate expected for a Fermi liquid. At high $T$, the spectral width decreases again towards the scattering rate of the classical, unitary Boltzmann gas, $backslashpropto T^-1/2$. In the transition region between the quantum degenerate and classical regime, the spectral width attains its maximum, on the scale of the Fermi energy, indicating the breakdown of a quasiparticle description. Density measurements in a harmonic trap directly reveal the majority dressing cloud surrounding the minority spins and yield the compressibility along with the effective mass of Fermi polarons. |
Nichols, Matthew A; Cheuk, Lawrence W; Okan, Melih; Hartke, Thomas R; Mendez, Enrique; Senthil, T; Khatami, Ehsan; Zhang, Hao; Zwierlein, Martin W Spin transport in a Mott insulator of ultracold fermions Journal Article In: Science, vol. 363, no. 6425, pp. 383–387, 2019, ISSN: 10959203. @article{Nichols2019, Strongly correlated materials are expected to feature unconventional transport properties, such that charge, spin, and heat conduction are potentially independent probes of the dynamics. In contrast to charge transport, the measurement of spin transport in such materials is highly challenging. We observed spin conduction and diffusion in a system of ultracold fermionic atoms that realizes the half-filled Fermi-Hubbard model. For strong interactions, spin diffusion is driven by super-exchange and doublon-hole--assisted tunneling, and strongly violates the quantum limit of charge diffusion. The technique developed in this work can be extended to finite doping, which can shed light on the complex interplay between spin and charge in the Hubbard model. |
2018 |
Rvachov, T M; Son, H; Park, J J; Ebadi, S; Zwierlein, M W; Ketterle, W; Jamison, A O Two-photon spectroscopy of the NaLi triplet ground state Journal Article In: Physical Chemistry Chemical Physics, vol. 20, no. 7, 2018, ISSN: 14639076. @article{Rvachov2018a, textcopyright the Owner Societies 2018. We employ two-photon spectroscopy to study the vibrational states of the triplet ground state potential (a 3 $Sigma$ + ) of the 23 Na 6 Li molecule. Pairs of Na and Li atoms in an ultracold mixture are photoassociated into an excited triplet molecular state, which in turn is coupled to vibrational states of the triplet ground potential. Vibrational state binding energies, line strengths, and potential fitting parameters for the triplet ground a 3 $Sigma$ + potential are reported. We also observe rotational splitting in the lowest vibrational state. |
Rvachov, T M; Son, H; Park, J J; Notz, P M; Wang, T T; Zwierlein, M W; Ketterle, W; Jamison, A O Photoassociation of ultracold NaLi Journal Article In: Physical Chemistry Chemical Physics, vol. 20, no. 7, 2018, ISSN: 14639076. @article{Rvachov2018b, textcopyright the Owner Societies 2018. We perform photoassociation spectroscopy in an ultracold 23 Na- 6 Li mixture to study the c 3 $Sigma$ + excited triplet molecular potential. We observe 50 vibrational states and their substructure to an accuracy of 20 MHz, and provide line strength data from photoassociation loss measurements. An analysis of the vibrational line positions using near-dissociation expansions and a full potential fit is presented. This is the first observation of the c 3 $Sigma$ + potential, as well as photoassociation in the NaLi system. |
2017 |
Rvachov, Timur M; Son, Hyungmok; Sommer, Ariel T; Ebadi, Sepehr; Park, Juliana J; Zwierlein, Martin W; Ketterle, Wolfgang; Jamison, Alan O Long-Lived Ultracold Molecules with Electric and Magnetic Dipole Moments Journal Article In: Physical Review Letters, vol. 119, no. 14, pp. 143001, 2017, ISSN: 0031-9007. @article{Rvachov2017, textcopyright 2017 American Physical Society. We create fermionic dipolar Na23Li6 molecules in their triplet ground state from an ultracold mixture of Na23 and Li6. Using magnetoassociation across a narrow Feshbach resonance followed by a two-photon stimulated Raman adiabatic passage to the triplet ground state, we produce 3×104 ground state molecules in a spin-polarized state. We observe a lifetime of 4.6 s in an isolated molecular sample, approaching the p-wave universal rate limit. Electron spin resonance spectroscopy of the triplet state was used to determine the hyperfine structure of this previously unobserved molecular state. |
Park, Jee Woo; Yan, Zoe Z; Loh, Huanqian; Will, Sebastian A; Zwierlein, Martin W Second-scale nuclear spin coherence time of ultracold 23 Na 40 K molecules Journal Article In: Science, vol. 357, no. 6349, pp. 372–375, 2017, ISSN: 0036-8075. @article{Park2017, Coherence, the stability of the relative phase between quantum states, lies at the heart of quantum mechanics. Applications such as precision measurement, interferometry, and quantum computation are enabled by physical systems that have quantum states with robust coherence. With the creation of molecular ensembles at sub-$backslashmu$K temperatures, diatomic molecules have become a novel system under full quantum control. Here, we report on the observation of stable coherence between a pair of nuclear spin states of ultracold fermionic NaK molecules in the singlet rovibrational ground state. Employing microwave fields, we perform Ramsey spectroscopy and observe coherence times on the scale of one second. This work opens the door for the exploration of single molecules as a versatile quantum memory. Switchable long-range interactions between dipolar molecules can further enable two-qubit gates, allowing quantum storage and processing in the same physical system. Within the observed coherence time, $10^4$ one- and two-qubit gate operations will be feasible. |
Fletcher, Richard J; Lopes, Raphael; Man, Jay; Navon, Nir; Smith, Robert P; Zwierlein, Martin W; Hadzibabic, Zoran Two- and three-body contacts in the unitary Bose gas Journal Article In: Science, vol. 355, no. 6323, pp. 377–380, 2017, ISSN: 0036-8075. @article{Fletcher2017, Tunable interactions make dilute atomic gases ideal for studying the collective dynamics of many-body systems. If the gas consists of strongly interacting fermions evenly divided into two groups of opposite spin, many of its properties can be distilled to two-body correlations. Fletcher et al. show that this does not hold for a gas of bosons, where identical particles happily congregate. The researchers measured a quantity that, in a thermal resonantly interacting Bose gas, depends only on three-body correlations. This enabled them to quantify the elusive correlations and establish unambiguously their effect on the physics of the many-body state.Science, this issue p. 377In many-body systems governed by pairwise contact interactions, a wide range of observables is linked by a single parameter, the two-body contact, which quantifies two-particle correlations. This profound insight has transformed our understanding of strongly interacting Fermi gases. Using Ramsey interferometry, we studied coherent evolution of the resonantly interacting Bose gas, and we show here that it cannot be explained by only pairwise correlations. Our experiments reveal the crucial role of three-body correlations arising from Efimov physics and provide a direct measurement of the associated three-body contact. |
Mukherjee, Biswaroop; Yan, Zhenjie; Patel, Parth B; Hadzibabic, Zoran; Yefsah, Tarik; Struck, Julian; Zwierlein, Martin W Homogeneous Atomic Fermi Gases Journal Article In: Physical Review Letters, vol. 118, no. 12, 2017, ISSN: 10797114. @article{Mukherjee2017, We report on the creation of homogeneous Fermi gases of ultracold atoms in a uniform potential. In the momentum distribution of a spin-polarized gas, we observe the emergence of the Fermi surface and the saturated occupation of one particle per momentum state. This directly confirms Pauli blocking in momentum space. For the spin-balanced unitary Fermi gas, we observe spatially uniform pair condensates. For thermodynamic measurements, we introduce a hybrid potential that is harmonic in one dimension and uniform in the other two. The spatially resolved compressibility reveals the superfluid transition in a spin-balanced Fermi gas, saturation in a fully polarized Fermi gas, and strong attraction in the polaronic regime of a partially polarized Fermi gas. |
2016 |
Cheuk, Lawrence W; Nichols, Matthew A; Lawrence, Katherine R; Okan, Melih; Zhang, Hao; Khatami, Ehsan; Trivedi, Nandini; Paiva, Thereza; Rigol, Marcos; Zwierlein, Martin W Observation of spatial charge and spin correlations in the 2D Fermi-Hubbard model Journal Article In: Science, vol. 353, no. 6305, pp. 1260–1264, 2016, ISSN: 0036-8075. @article{Cheuk2016a, |
Cheuk, Lawrence W; Nichols, Matthew A; Lawrence, Katherine R; Okan, Melih; Zhang, Hao; Zwierlein, Martin W Observation of 2D Fermionic Mott Insulators of 40K with Single-Site Resolution Journal Article In: Physical Review Letters, vol. 116, no. 23, pp. 235301, 2016, ISSN: 0031-9007. @article{Cheuk2016, ? 2016 American Physical Society.We report on the site-resolved observation of characteristic states of the two-dimensional repulsive Fermi-Hubbard model, using ultracold K40 atoms in an optical lattice. By varying the tunneling, interaction strength, and external confinement, we realize metallic, Mott-insulating, and band-insulating states. We directly measure the local moment, which quantifies the degree of on-site magnetization, as a function of temperature and chemical potential. Entropies per particle as low as 0.99(6)kB indicate that nearest-neighbor antiferromagnetic correlations should be detectable using spin-sensitive imaging. |
Will, Sebastian A; Park, Jee Woo; Yan, Zoe Z; Loh, Huanqian; Zwierlein, Martin W Coherent Microwave Control of Ultracold 23Na40K Molecules Journal Article In: Physical Review Letters, vol. 116, no. 22, pp. 225306, 2016, ISSN: 0031-9007. @article{Will2016, ? 2016 American Physical Society.We demonstrate coherent microwave control of rotational and hyperfine states of trapped, ultracold, and chemically stable Na23K40 molecules. Starting with all molecules in the absolute rovibrational and hyperfine ground state, we study rotational transitions in combined magnetic and electric fields and explain the rich hyperfine structure. Following the transfer of the entire molecular ensemble into a single hyperfine level of the first rotationally excited state |
Ku, Mark J H; Mukherjee, Biswaroop; Yefsah, Tarik; Zwierlein, Martin W Cascade of Solitonic Excitations in a Superfluid Fermi gas: From Planar Solitons to Vortex Rings and Lines Journal Article In: Physical Review Letters, vol. 116, no. 4, pp. 045304, 2016, ISSN: 0031-9007. @article{Ku2016, ? 2016 American Physical Society.We follow the time evolution of a superfluid Fermi gas of resonantly interacting Li6 atoms after a phase imprint. Via tomographic imaging, we observe the formation of a planar dark soliton, its subsequent snaking, and its decay into a vortex ring, which, in turn, breaks to finally leave behind a single solitonic vortex. In intermediate stages, we find evidence for an exotic structure resembling the ? soliton, a combination of a vortex ring and a vortex line. Direct imaging of the nodal surface reveals its undulation dynamics and its decay via the puncture of the initial soliton plane. The observed evolution of the nodal surface represents dynamics beyond superfluid hydrodynamics, calling for a microscopic description of unitary fermionic superfluids out of equilibrium. |
Zwierlein, M W Thermodynamics of strongly interacting Fermi gases Proceedings Article In: Proceedings of the International School of Physics "Enrico Fermi", 2016, ISSN: 18798195. @inproceedings{Zwierlein2016, textcopyright Società Italiana di Fisica. These lecture notes review the universal thermodynamics of strongly interacting Fermi gases, experimentally realized with ultracold atoms near Feshbach resonances. These gases serve as a pristine model system for fermionic matter with contact interactions. Over the recent years, their equation of state has been measured to an ever-increasing precision that allows distinguishing between different theoretical approaches to the many-fermion problem. In the spin-balanced, resonant case, the equation of state only depends on temperature and density. The superfluid transition is signaled by a lambda-like feature in the specific heat of the gas. For non-resonant interactions, the scattering length introduces a conjugate extensive thermodynamic quantity, the contact. It encodes the probability to find two particles in close proximity and thus governs the interaction energy of the gas, the tails of the momentum distribution, the wings and the mean transition frequency of radiofrequency spectra, the probability of photoassociation and other experimental quantities. Introducing spin imbalance allows addressing a fifty year old question on the fate of fermionic superfluidity when there are more up spins than down spins and pairing cannot be complete. Phase separation between the superfluid and a mixed normal phase, as well as the eventual breakdown of superfluidity at the Pauli or Clogston-Chandrasekhar limit, have been directly observed. The mixed normal phase is identified as a Fermi liquid of Fermi polarons, dressed quasi-particles with a modified effective mass and energy. Prospects of observing an inhomogeneous superfluid state, the Fulde-Ferrell-Larkin-Ovchinnikov state of mobile Cooper pairs, are briefly discussed. |
2015 |
Park, Jee Woo; Will, Sebastian A; Zwierlein, Martin W Two-photon pathway to ultracold ground state molecules of 23 Na 40 K Journal Article In: New Journal of Physics, vol. 17, no. 7, pp. 075016, 2015, ISSN: 1367-2630. @article{Park2015a, ? 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.We report on high-resolution spectroscopy of ultracold fermionic 23Na40K Feshbach molecules, and identify a two-photon pathway to the rovibrational singlet ground state via a resonantly mixed B1? ? c3?+intermediate state. Photoassociation in a 23Na-40K atomic mixture and one-photon spectroscopy on 23Na40K Feshbach molecules reveal about 20 vibrational levels of the electronically excited c3?+state. Two of these levels are found to be strongly perturbed by nearby B1? levels via spin-orbit coupling, resulting in additional lines of dominant singlet character in the perturbed complex, or of resonantly mixed character in . The dominantly singlet level is used to locate the absolute rovibrational singlet ground state via Autler-Townes spectroscopy. We demonstrate coherent two-photon coupling via dark state spectroscopy between the predominantly triplet Feshbach molecular state and the singlet ground state. Its binding energy is measured to be 5212.0447(1) cm-1, a thousand-fold improvement in accuracy compared to previous determinations. In their absolute singlet ground state, 23Na40K molecules are chemically stable under binary collisions and possess a large electric dipole moment of 2.72 Debye. Our work thus paves the way towards the creation of strongly dipolar Fermi gases of NaK molecules. |
Cheuk, Lawrence W; Nichols, Matthew A; Okan, Melih; Gersdorf, Thomas; Ramasesh, Vinay V; Bakr, Waseem S; Lompe, Thomas; Zwierlein, Martin W Quantum-Gas Microscope for Fermionic Atoms Journal Article In: Physical Review Letters, vol. 114, no. 19, pp. 193001, 2015, ISSN: 0031-9007. @article{Cheuk2015, ? 2015 American Physical Society.We realize a quantum-gas microscope for fermionic K40 atoms trapped in an optical lattice, which allows one to probe strongly correlated fermions at the single-atom level. We combine 3D Raman sideband cooling with high-resolution optics to simultaneously cool and image individual atoms with single-lattice-site resolution at a detection fidelity above 95%. The imaging process leaves the atoms predominantly in the 3D motional ground state of their respective lattice sites, inviting the implementation of a Maxwell's demon to assemble low-entropy many-body states. Single-site-resolved imaging of fermions enables the direct observation of magnetic order, time-resolved measurements of the spread of particle correlations, and the detection of many-fermion entanglement. |
Park, Jee Woo; Will, Sebastian A; Zwierlein, Martin W Ultracold Dipolar Gas of Fermionic 23Na40K Molecules in Their Absolute Ground State Journal Article In: Physical Review Letters, vol. 114, no. 20, pp. 205302, 2015. @article{Park2015, |
Zwierlein, M Ultracold atoms: How hot is the coldest matter? Journal Article In: Nature Physics, vol. 11, no. 9, 2015, ISSN: 17452481 17452473. @article{Zwierlein2015, |
2014 |
Ku, M J H; Ji, W; Mukherjee, B; Guardado-Sanchez, E; Cheuk, L W; Yefsah, T; Zwierlein, M W Motion of a solitonic vortex in the BEC-BCS crossover Journal Article In: Physical Review Letters, vol. 113, no. 6, pp. 065301, 2014, ISSN: 10797114 00319007. @article{Ku2014, We observe a long-lived solitary wave in a superfluid Fermi gas of Li6 atoms after phase imprinting. Tomographic imaging reveals the excitation to be a solitonic vortex, oriented transverse to the long axis of the cigar-shaped atom cloud. The precessional motion of the vortex is directly observed, and its period is measured as a function of the chemical potential in the BEC-BCS crossover. The long period and the correspondingly large ratio of the inertial to the bare mass of the vortex are in good agreement with estimates based on superfluid hydrodynamics that we derive here using the known equation of state in the BEC-BCS crossover. ? 2014 American Physical Society. |
Zwierlein, M W Superfluidity in ultracold atomic Fermi gases Book Section In: Bennemann, Karl-Heinz; Ketterson, John B (Ed.): Novel Superfluids, Vol. 2, Oxford University Press, Oxford, 2014. @incollection{Zwierlein2014, |
2013 |
Bakr, W; Cheuk, L W; Ku, M J -H; Park, J W; Sommer, A T; Will, S; Wu, C -H; Yefsah, T; Zwierlein, M W Strongly interacting Fermi gases Proceedings Article In: EPJ Web of Conferences, 2013, ISSN: 21016275 2100014X. @inproceedings{Bakr2013, Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state. ? Owned by the authors, published by EDP Sciences, 2013. |
Tey, M K; Sidorenkov, L A; Guajardo, E R S; Grimm, R; Ku, M J H; Zwierlein, M W; Hou, Y -H; Pitaevskii, L; Stringari, S Collective modes in a unitary fermi gas across the superfluid phase transition Journal Article In: Physical Review Letters, vol. 110, no. 5, 2013, ISSN: 00319007 10797114. @article{Tey2013, We provide a joint theoretical and experimental investigation of the temperature dependence of the collective oscillations of first sound nature exhibited by a highly elongated harmonically trapped Fermi gas at unitarity, including the region below the critical temperature for superfluidity. Differently from the lowest axial breathing mode, the hydrodynamic frequencies of the higher-nodal excitations show a temperature dependence, which is calculated starting from Landau two-fluid theory and using the available experimental knowledge of the equation of state. The experimental results agree with high accuracy with the predictions of theory and provide the first evidence for the temperature dependence of the collective frequencies near the superfluid phase transition. ? 2013 American Physical Society. |
Yefsah, T; Sommer, A T; Ku, M J H; Cheuk, L W; Ji, W; Bakr, W S; Zwierlein, M W Heavy solitons in a fermionic superfluid Journal Article In: Nature, vol. 499, no. 7459, 2013, ISSN: 00280836 14764687. @article{Yefsah2013, Solitons - solitary waves that maintain their shape as they propagate - occur as water waves in narrow canals, as light pulses in optical fibres and as quantum mechanical matter waves in superfluids and superconductors. Their highly nonlinear and localized nature makes them very sensitive probes of the medium in which they propagate. Here we create long-lived solitons in a strongly interacting superfluid of fermionic atoms and directly observe their motion. As the interactions are tuned from the regime of Bose-Einstein condensation of tightly bound molecules towards the Bardeen-Cooper-Schrieffer limit of long-range Cooper pairs, the solitons' effective mass increases markedly, to more than 200 times their bare mass, signalling strong quantum fluctuations. This mass enhancement is more than 50 times larger than the theoretically predicted value. Our work provides a benchmark for theories of non-equilibrium dynamics of strongly interacting fermions. ? 2013 Macmillan Publishers Limited. All rights reserved. |
Zwierlein, M W Shock cooling a universe Journal Article In: Nature Physics, vol. 9, no. 10, 2013, ISSN: 17452481 17452473. @article{Zwierlein2013, |
2012 |
Cheuk, L W; Sommer, A T; Hadzibabic, Z; Yefsah, T; Bakr, W S; Zwierlein, M W Spin-injection spectroscopy of a spin-orbit coupled Fermi gas Journal Article In: Physical Review Letters, vol. 109, no. 9, 2012, ISSN: 00319007 10797114. @article{Cheuk2012, The coupling of the spin of electrons to their motional state lies at the heart of recently discovered topological phases of matter. Here we create and detect spin-orbit coupling in an atomic Fermi gas, a highly controllable form of quantum degenerate matter. We directly reveal the spin-orbit gap via spin-injection spectroscopy, which characterizes the energy-momentum dispersion and spin composition of the quantum states. For energies within the spin-orbit gap, the system acts as a spin diode. We also create a spin-orbit coupled lattice and probe its spinful band structure, which features additional spin gaps and a fully gapped spectrum. In the presence of s-wave interactions, such systems should display induced p-wave pairing, topological superfluidity, and Majorana edge states. ? 2012 American Physical Society. |
Ku, M J H; Sommer, A T; Cheuk, L W; Zwierlein, M W Revealing the superfluid lambda transition in the universal thermodynamics of a unitary fermi gas Journal Article In: Science, vol. 335, no. 6068, 2012, ISSN: 10959203 00368075. @article{Ku2012, Fermi gases, collections of fermions such as neutrons and electrons, are found throughout nature, from solids to neutron stars. Interacting Fermi gases can form a superfluid or, for charged fermions, a superconductor. We have observed the superfluid phase transition in a strongly interacting Fermi gas by high-precision measurements of the local compressibility, density, and pressure. Our data completely determine the universal thermodynamics of these gases without any fit or external thermometer. The onset of superfluidity is observed in the compressibility, the chemical potential, the entropy, and the heat capacity, which displays a characteristic lambda-like feature at the critical temperature Tc/TF = 0.167(13). The ground-state energy is 3/5 ?N EF with ? = 0.376(4). Our measurements provide a benchmark for many-body theories of strongly interacting fermions. |
Park, J W; Wu, C -H; Santiago, I; Tiecke, T G; Will, S; Ahmadi, P; Zwierlein, M W Quantum degenerate Bose-Fermi mixture of chemically different atomic species with widely tunable interactions Journal Article In: Physical Review A - Atomic, Molecular, and Optical Physics, vol. 85, no. 5, 2012, ISSN: 10502947 10941622. @article{Park2012, We have created a quantum degenerate Bose-Fermi mixture of 23Na and 40K with widely tunable interactions via broad interspecies Feshbach resonances. Over 30 Feshbach resonances between 23Na and 40K were identified, including p-wave multiplet resonances. The large and negative triplet background scattering length between 23Na and 40K causes a sharp enhancement of the fermion density in the presence of a Bose condensate. As explained via the asymptotic bound-state model, this strong background scattering leads to wide Feshbach resonances observed at low magnetic fields. Our work opens up the prospect to create chemically stable, fermionic ground-state molecules of 23Na-40K, where strong, long-range dipolar interactions would set the dominant energy scale. ? 2012 American Physical Society. |
Sommer, A T; Cheuk, L W; Ku, M J H; Bakr, W S; Zwierlein, M W Evolution of fermion pairing from three to two dimensions Journal Article In: Physical Review Letters, vol. 108, no. 4, 2012, ISSN: 00319007 10797114. @article{Sommer2012, We follow the evolution of fermion pairing in the dimensional crossover from three-dimensional to two-dimensional as a strongly interacting Fermi gas of Li6 atoms becomes confined to a stack of two-dimensional layers formed by a one-dimensional optical lattice. Decreasing the dimensionality leads to the opening of a gap in radio-frequency spectra, even on the Bardeen-Cooper- Schrieffer side of a Feshbach resonance. The measured binding energy of fermion pairs closely follows the theoretical two-body binding energy and, in the two-dimensional limit, the zero-temperature mean-field Bose-Einstein- condensation to Bardeen-Cooper-Schrieffer crossover theory. ? 2012 American Physical Society. |
Houcke, K Van; Werner, F; Kozik, E; Prokof'Ev, N; Svistunov, B; Ku, M J H; Sommer, A T; Cheuk, L W; Schirotzek, A; Zwierlein, M W Feynman diagrams versus Fermi-gas Feynman emulator Journal Article In: Nature Physics, vol. 8, no. 5, 2012, ISSN: 17452473 17452481. @article{VanHoucke2012, Precise understanding of strongly interacting fermions, from electrons in modern materials to nuclear matter, presents a major goal in modern physics. However, the theoretical description of interacting Fermi systems is usually plagued by the intricate quantum statistics at play. Here we present a cross-validation between a new theoretical approach, bold diagrammatic Monte Carlo 1-3, and precision experiments on ultracold atoms. Specifically, we compute and measure, with unprecedented precision, the normal-state equation of state of the unitary gas, a prototypical example of a strongly correlated fermionic system 4-6. Excellent agreement demonstrates that a series of Feynman diagrams can be controllably resummed in a non-perturbative regime using bold diagrammatic Monte Carlo. ? 2012 Macmillan Publishers Limited. All rights reserved. |
Wu, C -H; Park, J W; Ahmadi, P; Will, S; Zwierlein, M W Ultracold fermionic Feshbach molecules of Na23K40 Journal Article In: Physical Review Letters, vol. 109, no. 8, 2012, ISSN: 00319007 10797114. @article{Wu2012, We report on the formation of ultracold weakly bound Feshbach molecules of Na23K40, the first fermionic molecule that is chemically stable in its absolute ground state. The lifetime of the nearly degenerate molecular gas exceeds 100ms in the vicinity of the Feshbach resonance. The measured dependence of the molecular binding energy on the magnetic field demonstrates the open-channel character of the molecules over a wide field range and implies significant singlet admixture. This will enable efficient transfer into the singlet vibrational ground state, resulting in a stable molecular Fermi gas with strong dipolar interactions. ? 2012 American Physical Society. |
2011 |
Pekker, D; Babadi, M; Sensarma, R; Zinner, N; Pollet, L; Zwierlein, M W; Demler, E Competition between pairing and ferromagnetic instabilities in ultracold Fermi gases near Feshbach resonances Journal Article In: Physical Review Letters, vol. 106, no. 5, 2011, ISSN: 00319007 10797114. @article{Pekker2011, We study the quench dynamics of a two-component ultracold Fermi gas from the weak into the strong interaction regime, where the short time dynamics are governed by the exponential growth rate of unstable collective modes. We obtain an effective interaction that takes into account both Pauli blocking and the energy dependence of the scattering amplitude near a Feshbach resonance. Using this interaction we analyze the competing instabilities towards Stoner ferromagnetism and pairing. ? 2011 American Physical Society. |
2024 |
Observation of chiral edge transport in a rapidly rotating quantum gas Journal Article In: Nature, vol. 20, iss. 11, pp. 1726–1731, 2024. |
Accelerating analysis of Boltzmann equations using Gaussian mixture models: Application to quantum Bose-Fermi mixtures Journal Article In: Physical Review Research, vol. 6, iss. 3, 2024. |
Collective flow of fermionic impurities immersed in a Bose–Einstein condensate Journal Article In: Nature Physics, vol. 20, pp. 1395–1400, 2024. |
Thermography of the superfluid transition in a strongly interacting Fermi gas Journal Article In: Science, vol. 383, iss. 6683, pp. 629–633, 2024. |
2023 |
Direct observation of nonlocal fermion pairing in an attractive Fermi-Hubbard gas Journal Article In: Science, vol. 381, iss. 6653, pp. 82–86, 2023. |
2022 |
Crystallization of bosonic quantum Hall states in a rotating quantum gas Journal Article In: Nature, vol. 601, pp. 58–62, 2022. |
Quantum register of fermion pairs Journal Article In: Nature, vol. 601, pp. 537–541, 2022. |
Resonant and first-order dipolar interactions between ultracold $upSigma$1 molecules in static and microwave electric fields Journal Article In: Phys. Rev. A, vol. 105, no. 1, 2022. |
2021 |
Supersolidity in Two-Dimensional Trapped Dipolar Droplet Arrays Journal Article In: Phys. Rev. Lett., vol. 127, no. 15, 2021. |
Pattern formation in quantum ferrofluids: From supersolids to superglasses Journal Article In: Phys. Rev. Research, vol. 3, no. 3, 2021. |
Geometric squeezing into the lowest Landau level Journal Article In: Science, vol. 372, no. 6548, pp. 1318–1322, 2021. |
Roton Excitations in an Oblate Dipolar Quantum Gas Journal Article In: Phys. Rev. Lett., vol. 126, no. 19, 2021. |
Density Fluctuations across the Superfluid-Supersolid Phase Transition in a Dipolar Quantum Gas Journal Article In: Phys. Rev. X, vol. 11, no. 1, 2021. |
Quantum Simulators: Architectures and Opportunities Journal Article In: PRX Quantum Quantum, vol. 2, no. 1, 2021. |
2020 |
Universal Sound Diffusion in a Strongly Interacting Fermi Gas Journal Article In: Science, vol. 370, pp. 1222-1226, 2020. |
Doublon-Hole Correlations and Fluctuation Thermometry in a Fermi-Hubbard Gas Journal Article In: Phys. Rev. Lett., vol. 125, no. 11, 2020. |
Bose polarons near quantum criticality Journal Article In: Science, vol. 368, pp. 190-194, 2020. |
Resonant dipolar collisions of ultracold molecules induced by microwave dressing Journal Article In: Phys. Rev. Lett., vol. 125, pp. 063401, 2020. |
2019 |
Photoinduced Two-Body Loss of Ultracold Molecules Journal Article In: Physical Review Letters, vol. 123, no. 12, 2019, ISSN: 10797114. |
Spectral Response and Contact of the Unitary Fermi Gas Journal Article In: Physical Review Letters, vol. 122, no. 20, pp. 203402, 2019. |
Boiling a Unitary Fermi Liquid Journal Article In: Physical Review Letters, vol. 122, no. 9, 2019, ISSN: 10797114. |
Spin transport in a Mott insulator of ultracold fermions Journal Article In: Science, vol. 363, no. 6425, pp. 383–387, 2019, ISSN: 10959203. |
2018 |
Two-photon spectroscopy of the NaLi triplet ground state Journal Article In: Physical Chemistry Chemical Physics, vol. 20, no. 7, 2018, ISSN: 14639076. |
Photoassociation of ultracold NaLi Journal Article In: Physical Chemistry Chemical Physics, vol. 20, no. 7, 2018, ISSN: 14639076. |
2017 |
Long-Lived Ultracold Molecules with Electric and Magnetic Dipole Moments Journal Article In: Physical Review Letters, vol. 119, no. 14, pp. 143001, 2017, ISSN: 0031-9007. |
Second-scale nuclear spin coherence time of ultracold 23 Na 40 K molecules Journal Article In: Science, vol. 357, no. 6349, pp. 372–375, 2017, ISSN: 0036-8075. |
Two- and three-body contacts in the unitary Bose gas Journal Article In: Science, vol. 355, no. 6323, pp. 377–380, 2017, ISSN: 0036-8075. |
Homogeneous Atomic Fermi Gases Journal Article In: Physical Review Letters, vol. 118, no. 12, 2017, ISSN: 10797114. |
2016 |
Observation of spatial charge and spin correlations in the 2D Fermi-Hubbard model Journal Article In: Science, vol. 353, no. 6305, pp. 1260–1264, 2016, ISSN: 0036-8075. |
Observation of 2D Fermionic Mott Insulators of 40K with Single-Site Resolution Journal Article In: Physical Review Letters, vol. 116, no. 23, pp. 235301, 2016, ISSN: 0031-9007. |
Coherent Microwave Control of Ultracold 23Na40K Molecules Journal Article In: Physical Review Letters, vol. 116, no. 22, pp. 225306, 2016, ISSN: 0031-9007. |
Cascade of Solitonic Excitations in a Superfluid Fermi gas: From Planar Solitons to Vortex Rings and Lines Journal Article In: Physical Review Letters, vol. 116, no. 4, pp. 045304, 2016, ISSN: 0031-9007. |
Thermodynamics of strongly interacting Fermi gases Proceedings Article In: Proceedings of the International School of Physics "Enrico Fermi", 2016, ISSN: 18798195. |
2015 |
Two-photon pathway to ultracold ground state molecules of 23 Na 40 K Journal Article In: New Journal of Physics, vol. 17, no. 7, pp. 075016, 2015, ISSN: 1367-2630. |
Quantum-Gas Microscope for Fermionic Atoms Journal Article In: Physical Review Letters, vol. 114, no. 19, pp. 193001, 2015, ISSN: 0031-9007. |
Ultracold Dipolar Gas of Fermionic 23Na40K Molecules in Their Absolute Ground State Journal Article In: Physical Review Letters, vol. 114, no. 20, pp. 205302, 2015. |
Ultracold atoms: How hot is the coldest matter? Journal Article In: Nature Physics, vol. 11, no. 9, 2015, ISSN: 17452481 17452473. |
2014 |
Motion of a solitonic vortex in the BEC-BCS crossover Journal Article In: Physical Review Letters, vol. 113, no. 6, pp. 065301, 2014, ISSN: 10797114 00319007. |
Superfluidity in ultracold atomic Fermi gases Book Section In: Bennemann, Karl-Heinz; Ketterson, John B (Ed.): Novel Superfluids, Vol. 2, Oxford University Press, Oxford, 2014. |
2013 |
Strongly interacting Fermi gases Proceedings Article In: EPJ Web of Conferences, 2013, ISSN: 21016275 2100014X. |
Collective modes in a unitary fermi gas across the superfluid phase transition Journal Article In: Physical Review Letters, vol. 110, no. 5, 2013, ISSN: 00319007 10797114. |
Heavy solitons in a fermionic superfluid Journal Article In: Nature, vol. 499, no. 7459, 2013, ISSN: 00280836 14764687. |
Shock cooling a universe Journal Article In: Nature Physics, vol. 9, no. 10, 2013, ISSN: 17452481 17452473. |
2012 |
Spin-injection spectroscopy of a spin-orbit coupled Fermi gas Journal Article In: Physical Review Letters, vol. 109, no. 9, 2012, ISSN: 00319007 10797114. |
Revealing the superfluid lambda transition in the universal thermodynamics of a unitary fermi gas Journal Article In: Science, vol. 335, no. 6068, 2012, ISSN: 10959203 00368075. |
Quantum degenerate Bose-Fermi mixture of chemically different atomic species with widely tunable interactions Journal Article In: Physical Review A - Atomic, Molecular, and Optical Physics, vol. 85, no. 5, 2012, ISSN: 10502947 10941622. |
Evolution of fermion pairing from three to two dimensions Journal Article In: Physical Review Letters, vol. 108, no. 4, 2012, ISSN: 00319007 10797114. |
Feynman diagrams versus Fermi-gas Feynman emulator Journal Article In: Nature Physics, vol. 8, no. 5, 2012, ISSN: 17452473 17452481. |
Ultracold fermionic Feshbach molecules of Na23K40 Journal Article In: Physical Review Letters, vol. 109, no. 8, 2012, ISSN: 00319007 10797114. |
2011 |
Competition between pairing and ferromagnetic instabilities in ultracold Fermi gases near Feshbach resonances Journal Article In: Physical Review Letters, vol. 106, no. 5, 2011, ISSN: 00319007 10797114. |