scholarly journals Strongly interacting Fermi systems in1/Nexpansion: From cold atoms to color superconductivity

2008 ◽  
Vol 78 (12) ◽  
Author(s):  
Hiroaki Abuki ◽  
Tomáš Brauner
Keyword(s):  
Cold Atoms ◽  
Color Superconductivity ◽  
Fermi Systems ◽  
Strongly Interacting ◽  
Strongly Interacting Fermi Systems

TWO–PARTICLE–TWO–HOLE EXCITATIONS IN 3He

2006 ◽  
Vol 20 (19) ◽  
pp. 2657-2666
Author(s):  
E. KROTSCHECK ◽  
H. M. BÖHM ◽  
K. SCHÖRKHUBER
Keyword(s):  
Random Phase Approximation ◽  
Equations Of Motion ◽  
Random Phase ◽  
Dynamic Structure ◽  
Fermi Systems ◽  
Effective Interactions ◽  
Pair Correlations ◽  
Dependent Pair ◽  
Strongly Interacting ◽  
Strongly Interacting Fermi Systems

We describe the development of a systematic theory of excitations in strongly interacting Fermi systems. Technically, we derive the equations of motion for multi–pair excitations from a stationarity principle. This method has, in Fermi systems, so far been developed only to the level of one–particle–one–hole excitations, where it leads to the (correlated) random phase approximation (RPA). We extend the analysis here to pair excitations. Our work is motivated by the fact that time–dependent pair correlations are necessary for explaining the physics of the phonon–roton spectrum in 4 He . It is therefore plausible that the same processes also have visible effects in the excitation spectrum of 3 He . Further motivation is derived from recent measurements of the dynamic structure function in two–dimensional 3 He . We first formulate the theory for a second quantized, weakly interacting Hamiltonian and then generalize the theory to a correlated ground state. We show that the inclusion of Jastrow–Feenberg type correlations leads to prescriptions for calculating weak effective interactions from a microscopic, strongly interacting Hamiltonian.

scholarly journals Equivalence of Dissipative and Dissipationless Dynamics of Interacting Quantum Systems With Its Application to the Unitary Fermi Gas

2021 ◽  
Vol 9 ◽  
Author(s):  
Masaaki Tokieda ◽  
Shimpei Endo
Keyword(s):  
Quantum Dynamics ◽  
Cold Atoms ◽  
Fermi Gas ◽  
Quantum Systems ◽  
Harmonic Potential ◽  
Particle Interactions ◽  
Dissipative Dynamics ◽  
Strongly Interacting ◽  
Unitary Fermi Gas

We analytically study quantum dissipative dynamics described by the Caldirola-Kanai model with inter-particle interactions. We have found that the dissipative quantum dynamics of the Caldirola-Kanai model can be exactly mapped to a dissipationless quantum dynamics under a negative external harmonic potential, even when the particles are strongly interacting. In particular, we show that the mapping is valid for the unitary Fermi gas, which is relevant for cold atoms and nuclear matters.

BREAKING TRANSLATIONAL INVARIANCE BY POPULATION IMBALANCE: THE FULDE–FERRELL–LARKIN–OVCHINNIKOV STATES

2010 ◽  
Vol 24 (20n21) ◽  
pp. 3915-3949 ◽  
Author(s):  
Gertrud Zwicknagl ◽  
Jochen Wosnitza
Keyword(s):  
Cold Atoms ◽  
Fermi Systems ◽  
Translational Invariance ◽  
Fermion Systems ◽  
Theoretical Approaches ◽  
Wide Range ◽  
Translation Symmetry ◽  
Experimental Side ◽  
Population Imbalance ◽  
Present Understanding

An overview is given of our present understanding of superconductivity with spontaneously broken translation symmetry in polarized Fermi systems. The existence of "crystalline" superconducting phases is considered in a wide range of systems, prominent examples being conduction electrons in metals, ultra-cold atoms in a trap, nuclear matter and dense quark systems. The underlying physics is delineated and theoretical approaches to the inhomogeneous phases and their properties are discussed. From the experimental side, it is argued that superconductivity with imbalance-induced order parameters is realized in layered organic compounds and potentially in heavy-fermion systems.

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