Keywords:
Electronic books.
Description / Table of Contents:
The field of cold atomic gases faced a revolution in 1995 when Bose-Einstein condensation was achieved. Since then, there has been an impressive progress, both experimental and theoretical. The quest for ultra-cold Fermi gases started shortly after the 1995 discovery, and quantum degeneracy in a gas of fermionic atoms was obtained in 1999. The Pauli exclusion principle plays a crucial role in many aspects of ultra-cold Fermi gases, including inhibited interactions with applications to precision measurements, and strong correlations. The path towards strong interactions and pairing of fermions opened up with the discovery in 2003 that molecules formed by fermions near a Feshbach resonance were surprisingly stable against inelastic decay, but featured strong elastic interactions. This remarkable combination was explained by the Pauli exclusion principle and the fact that only inelastic collisions require three fermions to come close to each other. The unexpected stability of strongly interacting fermions and fermion pairs triggered most of the research which was presented at this summer school. It is remarkable foresight (or good luck) that the first steps to organize this summer school were already taken before this discovery. It speaks for the dynamics of the field how dramatically it can change course when new insight is obtained. The contributions in this volume provide a detailed coverage of the experimental techniques for the creation and study of Fermi quantum gases, as well as the theoretical foundation for understanding the properties of these novel systems.
Type of Medium:
Online Resource
Pages:
1 online resource (933 pages)
Edition:
1st ed.
ISBN:
9781607503187
Series Statement:
International School of Physics Enrico Fermi Series ; v.164
URL:
https://ebookcentral.proquest.com/lib/geomar/detail.action?docID=363201
Language:
English
Note:
Intro -- Indice -- Preface -- Gruppo fotografico dei partecipanti al Corso -- Fermi gas experiments -- 1. Introduction -- 1.1. Why study ultracold Fermi gases? -- 1.2. Superfluidity -- 1.3. Pairing of fermions -- 1.4. BCS-BEC crossover physics -- 1.5. Status of field -- 2. Weakly interacting Fermi gas -- 2.1. Creating a Fermi gas of atoms -- 2.2. Thermodynamics -- 2.3. Thermometry using the momentum distribution -- 2.4. Thermometry using an impurity spin state -- 3. Feshbach resonance -- 3.1. Predictions -- 3.2. Collisions -- 3.3. Anisotropic expansion -- 3.4. Interaction energy -- 4. Feshbach molecules -- 4.1. Molecule creation -- 4.2. Molecule binding energy -- 4.3. Molecule conversion efficiency -- 4.4. Long-lived molecules -- 5. Condensates in a Fermi gas -- 5.1. Molecular condensates -- 5.2. Fermi condensates -- 5.3. Measurement of a phase diagram -- 6. Exploring the BCS-BEC crossover -- 6.1. Excitations -- 6.2. Atom noise -- 6.3. Thermodynamics -- 7. Conclusion -- Dynamics and superfluidity of an ultracold Fermi gas -- 1. Introduction -- 2. Ideal Fermi gas in harmonic trap -- 3. Role of interactions: The BEC-BCS crossover -- 4. Equilibrium properties of a trapped gas -- 5. Dynamics and superfluidity -- 6. Rotating Fermi gases and superfluidity -- 7. Conclusions -- Making, probing and understanding ultracold Fermi gases -- 1. Introduction -- 1.1. State of the field -- 1.2. Strongly correlated fermions-a gift of nature? -- 1.3. Some remarks on the history of fermionic superfluidity -- 1.4. Realizing model systems with ultracold atoms -- 1.5. Overview over the sections -- 2. Experimental techniques -- 2.1. The atoms -- 2.2. Cooling and trapping techniques -- 2.3. RF spectroscopy -- 2.4. Using and characterizing Feshbach resonances -- 2.5. Techniques to observe cold atoms and molecules -- 3. Quantitative analysis of density distributions.
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3.1. Trapped atomic gases -- 3.2. Expansion of strongly interacting Fermi mixtures -- 3.3. Fitting functions for trapped and expanded Fermi gases -- 4. Theory of the BEC-BCS crossover -- 4.1. Elastic collisions -- 4.2. Pseudo-potentials -- 4.3. Cooper instability in a Fermi gas with attractive interactions -- 4.4. Crossover wave function -- 4.5. Gap and number equation -- 4.6. Discussion of the three regimes-BCS, BEC and crossover -- 4.7. Single-particle and collective excitations -- 4.8. Finite temperatures -- 4.9. Long-range order and condensate fraction -- 4.10. Superfluid density -- 4.11. Order parameter and Ginzburg-Landau equation -- 4.12. Crossing over from BEC to BCS -- 5. Feshbach resonances -- 5.1. History and experimental summary -- 5.2. Scattering resonances -- 5.3. Feshbach resonances -- 5.4. Broad versus narrow Feshbach resonances -- 5.5. Open channel resonance and the case of [sup(6)]Li -- 6. Condensation and superfluidity across the BEC-BCS crossover -- 6.1. Bose-Einstein condensation and superfluidity -- 6.2. Signatures for superfluidity in quantum gases -- 6.3. Pair condensation below the Feshbach resonance -- 6.4. Pair condensation above the Feshbach resonance -- 6.5. Direct observation of condensation in the density profiles -- 6.6. Observation of vortex lattices -- 7. BEC-BCS crossover: Energetics, excitations, and new systems -- 7.1. Characterization of the equilibrium state -- 7.2. Studies of excitations -- 7.3. New systems with BEC-BCS crossover -- 8. Conclusion -- Basic theory tools for degenerate Fermi gases -- 1. The ideal Fermi gas -- 1.1. Basic facts -- 1.2. Coherence and correlation functions of the homogeneous gas -- 1.3. Fluctuations of the number of fermions in a given spatial zone -- 1.4. Application to the 1D gas of impenetrable bosons -- 1.5. In a harmonic trap -- 2. Two-body aspects of the interaction potential.
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2.1. Which model for the interaction potential? -- 2.2. Reminder of scattering theory -- 2.3. Effective-range expansion and various physical regimes -- 2.4. A two-channel model -- 2.5. The Bethe-Peierls model -- 2.6. The lattice model -- 2.7. Application of Bethe-Peierls to a toy model: two macroscopic branches -- 3. Zero-temperature BCS theory: Study of the ground branch -- 3.1. The BCS ansatz -- 3.2. Energy minimization within the BCS family -- 3.3. Reminder on diagonalization of quadratic Hamiltonians -- 3.4. Summary of BCS results for the homogeneous system -- 3.5. Derivation of superfluid hydrodynamic equations from BCS theory -- Two-channel models of the BCS/BEC crossover -- 1. Introduction -- 2. Bose-Einstein condensation and superfluidity -- 3. Description of a superfluid in a dilute atomic gas -- 4. Breakdown of the mean-field picture-resonance superfluids -- 5. Single-channel vs. two-channel approaches -- 6. Poles of the molecular propagator -- 7. The equivalent single-channel theory -- 8. Connection with the theory of Feshbach resonances -- 9. The BCS/BEC crossover -- 10. Momentum distribution in a dilute Fermi gas -- 11. Imaginary-time methods for single- and two-channel BCS models -- 11.1. Single-channel BCS theory -- 11.2. Imaginary-time propagation for bosons -- 11.3. Imaginary-time propagation for fermions -- 11.4. Imaginary-time algorithm for the single-channel model -- 11.5. Imaginary-time propagation for the two-channel model -- 12. A mean-field description for the crossover problem -- 12.1. Boson scattering length -- 12.2. Beyond pair correlations -- 13. Summary -- Molecular regimes in ultracold Fermi gases -- Introduction -- 1. Lecture 1. Diatomic molecules in a two-component Fermi gas -- 1.1. Feshbach resonances and diatomic molecules -- 1.2. Weakly interacting gas of bosonic molecules. Molecule-molecule elastic interaction.
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1.3. Suppression of collisional relaxation -- 1.4. Prospects for manipulations with weakly bound molecules -- 2. Lecture 2. Molecular regimes in Fermi-Fermi mixtures -- 2.1. Influence of the mass ratio on the elastic intermolecular interaction -- 2.2. Collisional relaxation. Exact results and qualitative analysis -- 2.3. Molecules of heavy and light fermionic atoms -- 2.4. Crystalline molecular phase -- Ultracold Fermi gases in the BEC-BCS crossover: A review from the Innsbruck perspective -- 1. Introduction -- 2. Brief history of experiments on strongly interacting Fermi gases -- 3. Interactions in a [sup(6)]Li spin mixture -- 3.1. Energy levels of [sup(6)]Li atoms in a magnetic field -- 3.2. Tunability at the marvelous 834G Feshbach resonance -- 3.3. Weakly bound dimers -- 4. The molecular route into Fermi degeneracy: creation of a molecular Bose-Einstein condensate -- 4.1. A brief review of different approaches -- 4.2. The all-optical Innsbruck approach -- 4.3. Formation of weakly bound molecules -- 4.4. Evaporative cooling of an atom-molecule mixture -- 4.5. The appearance of mBEC -- 5. Crossover from mBEC to a fermionic superfluid -- 5.1. BEC-BCS crossover physics: a brief introduction -- 5.2. Basic definitions, typical experimental parameters -- 5.3. Universal Fermi gas in the unitarity limit -- 5.4. Equation of state -- 5.5. Phase diagram, relevant temperatures and energies -- 5.6. First Innsbruck crossover experiments: conservation of entropy, spatial profiles, and potential energy of the trapped gas -- 6. Collective excitations in the BEC-BCS crossover -- 6.1. Basics of collective modes -- 6.2. Overview of recent experiments -- 6.3. Axial mode -- 6.4. Radial breathing mode: breakdown of hydrodynamics -- 6.5. Precision test of the equation of state -- 6.6. Other modes of interest -- 7. Pairing gap spectroscopy in the BEC-BCS crossover.
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7.1. Basics of radio-frequency spectroscopy -- 7.2. RF spectroscopy on weakly bound molecules -- 7.3. Observation of the pairing gap in the crossover -- 8. Conclusion and outlook -- A lab in a trap: Fermionic quantum gases, Bose-Fermi mixtures and molecules in optical lattices -- 1. Introduction -- 2. Optical lattices -- 3. Concept of the experiment -- 4. Imaging Fermi surfaces -- 5. Interacting fermionic atoms in an optical lattice: the Hubbard model and beyond -- 6. Weakly bound molecules in an optical lattice -- 7. Bose-Fermi mixtures in a three-dimensional optical lattice -- 8. Outlook -- Condensed-matter physics with light and atoms: Strongly correlated cold fermions in optical lattices -- 1. Introduction: A novel condensed-matter physics -- 2. Considerations on energy scales -- 3. When do we have a Hubbard model? -- 4. The Mott phenomenon -- 4.1. Mean-field theory of the bosonic Hubbard model -- 4.2. Incompressibility of the Mott phase and "wedding-cake" structure of the density profile in the trap -- 4.3. Fermionic Mott insulators and the Mott transition in condensedmatter physics -- 4.4. (Dynamical) mean-field theory for fermionic systems -- 5. Ground state of the 2-component Mott insulator: Antiferromagnetism -- 6. Adiabatic cooling: Entropy as a thermometer -- 7. The key role of frustration -- 7.1. Frustration can reveal "genuine" Mott physics -- 7.2. Frustration can lead to exotic quantum magnetism -- 8. Quasi-particle excitations in strongly correlated fermion systems, and how to measure them -- 8.1. Response functions and their relation to the spectrum of excitations -- 8.2. Measuring one-particle excitations by stimulated Raman scattering -- 8.3. Excitations in interacting Fermi systems: A crash course -- 8.4. Elusive quasi-particles and nodal-antinodal dichotomy: The puzzles of cuprate superconductors.
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Quantum information processing: Basic concepts and implementations with atoms.
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