Observation of pair condensation in the quasi-2D BEC-BCS crossover

Abstract

The condensation of fermion pairs lies at the heart of superfluidity. However, for strongly correlated systems with reduced dimensionality the mechanisms of pairing and condensation are still not fully understood. In our experiment we use ultracold atoms as a generic model system to study the phase transition from a normal to a condensed phase in a strongly interacting quasi-two-dimensional Fermi gas. Using a novel method, we obtain the in situ pair momentum distribution of the strongly interacting system and observe the emergence of a low-momentum condensate at low temperatures. By tuning temperature and interaction strength we map out the phase diagram of the quasi-2D BEC-BCS crossover.

References in corpus (14)

• Many-Body Physics with Ultracold Gases
• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Attractive and repulsive Fermi polarons in two dimensions
• Observation of scale invariance and universality in two-dimensional Bose gases
• Radiofrequency spectroscopy of a strongly interacting two-dimensional Fermi gas
• Strong saturation absorption imaging of dense clouds of ultracold atoms
• Superfluid behaviour of a two-dimensional Bose gas
• Observation of a two-dimensional Fermi gas of atoms
• Crossover from 2D to 3D in a weakly interacting Fermi gas
• Improved detection of small atom numbers through image processing
• Matter wave Fourier optics with a strongly interacting two-dimensional Fermi gas
• Quasi-two-dimensional Fermi gases at finite temperature
• Pseudogap phenomena in a two-dimensional ultracold Fermi gas near the Berezinskii-Kosterlitz-Thouless transition

Cited by in corpus (12)

• Observation of the Berezinskii-Kosterlitz-Thouless Phase Transition in an Ultracold Fermi Gas
• Spin-Imbalanced Quasi-Two-Dimensional Fermi Gases
• Loading and compression of a single two-dimensional Bose gas in an optical accordion
• Connecting Berezinskii-Kosterlitz-Thouless and BEC phase transitions by tuning interactions in a trapped gas
• Nonperturbative renormalization group treatment of amplitude fluctuations for $|\phi {|}^4$ topological phase transitions
• Visualizing the BEC-BCS crossover in the two-dimensional Fermi gas: pairing gaps and dynamical response functions from ab initio computations
• Thermodynamic equivalence of two-dimensional imperfect attractive Fermi and repulsive Bose gases
• Quantum fluctuations and vortex-antivortex unbinding in the 2D BCS-BEC crossover
• Kosterlitz-Thouless transition and vortex-antivortex lattice melting in two-dimensional Fermi gases with $p$- or $d$-wave pairing
• Interplay between Rashba spin-orbit coupling and adiabatic rotation in a two-dimensional Fermi gas
• Pseudogap regime of a two-dimensional uniform Fermi gas
• Pseudogap phenomena near the BKT transition of a two-dimensional ultracold Fermi gas in the crossover region