Quasipure Bose-Einstein Condensate Immersed in a Fermi Sea

Schreck, Florian; Khaykovich, Lev; Corwin, Kristan L.; Ferrari, G.; Bourdel, Thomas; Cubizolles, J.; Salomon, Christophe

doi:10.1103/physrevlett.87.080403

Cited by 793 publications

(743 citation statements)

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“…The basic ingredients required for the experimental implementation of our proposal are the following: (a) a quantum-degenerate Bose-Fermi [29][30][31][32][33][34][35][36] or Fermi-Fermi [37][38][39][40][41][42][43] mixture, (b) the ability to trap one type of atom by a strong optical-lattice potential, (c) the control of the interaction strength between the impurity and host atom, which is achieved by changing the impurity hyperfine state, and (d) the ability to achieve temperatures that are low enough to observe the OC.…”

Section: Discussionmentioning

confidence: 99%

Time-Dependent Impurity in Ultracold Fermions: Orthogonality Catastrophe and Beyond

et al. 2012

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The recent experimental realization of strongly imbalanced mixtures of ultracold atoms opens new possibilities for studying impurity dynamics in a controlled setting. In this paper, we discuss how the techniques of atomic physics can be used to explore new regimes and manifestations of Anderson's orthogonality catastrophe (OC), which could not be accessed in solid-state systems. Specifically, we consider a system of impurity atoms, localized by a strong optical-lattice potential, immersed in a sea of itinerant Fermi atoms. We point out that the Ramsey-interference-type experiments with the impurity atoms allow one to study the OC in the time domain, while radio-frequency (RF) spectroscopy probes the OC in the frequency domain. The OC in such systems is universal, not only in the long-time limit, but also for all times and is determined fully by the impurity-scattering length and the Fermi wave vector of the itinerant fermions. We calculate the universal Ramsey response and RF-absorption spectra. In addition to the standard power-law contributions, which correspond to the excitation of multiple particle-hole pairs near the Fermi surface, we identify a novel, important contribution to the OC that comes from exciting one extra particle from the bottom of the itinerant band. This contribution gives rise to a nonanalytic feature in the RF-absorption spectra, which shows a nontrivial dependence on the scattering length, and evolves into a true power-law singularity with the universal exponent 1=4 at the unitarity. We extend our discussion to spin-echo-type experiments, and show that they probe more complicated nonequilibirum dynamics of the Fermi gas in processes in which an impurity switches between states with different interaction strength several times; such processes play an important role in the Kondo problem, but remained out of reach in the solid-state systems. We show that, alternatively, the OC can be seen in the energy-counting statistics of the Fermi gas following a sudden quench of the impurity state. The energy distribution function, which can be measured in time-of-flight experiments, exhibits characteristic power-law singularities at low energies. Finally, systems in which the itinerant fermions have two or more hyperfine states provide an even richer playground for studying nonequilibrium impurity physics, allowing one to explore the nonequilibrium OC and even to simulate quantum transport through nanostructures. This provides a previously missing connection between cold atomic systems and mesoscopic quantum transport.

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Section: Discussionmentioning

confidence: 99%

Time-Dependent Impurity in Ultracold Fermions: Orthogonality Catastrophe and Beyond

et al. 2012

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“…Recent successful observation of condensed bosonfermion mixtures of trapped alkali-metal atoms by different experimental groups [1][2][3][4] has initiated the intensive experimental studies of different novel phenomena [5][6][7] . Among these experiments there have been studies of condensate of two components of 40 K [1] and 6 Li [2] atoms.…”

Section: Introductionmentioning

confidence: 99%

Mean-field description of a dynamical collapse of a fermionic condensate in a trapped boson-fermion mixture

Adhikari¹

2004

Phys. Rev. A

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We suggest a time-dependent dynamical mean-field-hydrodynamic model for the collapse of a trapped boson-fermion condensate and perform numerical simulation based on it to understand some aspects of the experiment by Modugno et al. [Science 297, 2240] on the collapse of the fermionic condensate in the 40 K-87 Rb mixture. We show that the mean-field model explains the formation of a stationary boson-fermion condensate at zero temperature with relative sizes compatible with experiment. This model is also found to yield a faithful representation of the collapse dynamics in qualitative agreement with experiment. In particular we consider the collapse of the fermionic condensate associated with (a) an increase of the number of bosonic atoms as in the experiment and (b) an increase of the attractive boson-fermion interaction using a Feshbach resonance. Suggestion for experiments of fermionic collapse using a Feshbach resonance is made.

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“…[3]. We simulate the evaporative cooling of a system, starting with N f = 4 × 10 3 fermions and N b = 10 6 bosonic atoms at an initial temperature of T = 9 µK which is 6.12 times the Fermi temperature for this amount of fermions.…”

Section: A Evaporating the Bosonic Atomsmentioning

confidence: 99%

“…In the experiments on sympathetic cooling by Schreck et al [3,8] a mixture of bosons and fermions is cooled from 2 mK to around 9 µK, starting with 2 × 10 8 7 Li bosons and about 10 6 6 Li fermions, in an anisotropic trap (ω r = 2π × 4050 Hz, ω a = 2π × 71.17 Hz). We have simulated this process and compared with the experimental data [8].…”

Section: A Evaporating the Bosonic Atomsmentioning

confidence: 99%

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Three-fluid description of the sympathetic cooling of a boson-fermion mixture

Wouters

Tempere²,

Devreese

2002

Phys. Rev. A

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We present a model for sympathetic cooling of a mixture of fermionic and bosonic atomic gases in harmonic traps, based on a three-fluid description.The model confirms the experimentally observed cooling limit of about 0.2 T F when only bosons are pumped. We propose sequential cooling -first pumping of bosons and afterwards fermions -as a way to obtain lower temperatures.For this scheme, our model predicts that temperatures less than 0.1 T F can be reached.

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Quasipure Bose-Einstein Condensate Immersed in a Fermi Sea

Cited by 793 publications

References 20 publications

Time-Dependent Impurity in Ultracold Fermions: Orthogonality Catastrophe and Beyond

Time-Dependent Impurity in Ultracold Fermions: Orthogonality Catastrophe and Beyond

Mean-field description of a dynamical collapse of a fermionic condensate in a trapped boson-fermion mixture

Three-fluid description of the sympathetic cooling of a boson-fermion mixture

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