Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with Pseudogap
Recent experimental progress allows for exploring some important physical quantities of ultracold Fermi gases, such as the compressibility, spin susceptibility, viscosity, optical conductivity, and spin diffusivity. Theoretically, these quantities can be evaluated from suitable linear response theor...
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Wiley
2015-01-01
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| Series: | Advances in Condensed Matter Physics |
| Online Access: | http://dx.doi.org/10.1155/2015/582734 |
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| author | Hao Guo Yan He |
| author_facet | Hao Guo Yan He |
| author_sort | Hao Guo |
| collection | DOAJ |
| description | Recent experimental progress allows for exploring some important physical quantities of ultracold Fermi gases, such as the compressibility, spin susceptibility, viscosity, optical conductivity, and spin diffusivity. Theoretically, these quantities can be evaluated from suitable linear response theories. For BCS superfluid, it has been found that the gauge invariant linear response theories can be fully consistent with some stringent consistency constraints. When the theory is generalized to stronger than BCS regime, one may meet serious difficulties to satisfy the gauge invariance conditions. In this paper, we try to construct density and spin linear response theories which are formally gauge invariant for a Fermi gas undergoing BCS-Bose-Einstein Condensation (BEC) crossover, especially below the superfluid transition temperature Tc. We adapt a particular t-matrix approach which is close to the G0G formalism to incorporate noncondensed pairing in the normal state. We explicitly show that the fundamental constraints imposed by the Ward identities and Q-limit Ward identity are indeed satisfied. |
| format | Article |
| id | doaj-art-182f0f5e93a04172a1ba164ba4eeecce |
| institution | Kabale University |
| issn | 1687-8108 1687-8124 |
| language | English |
| publishDate | 2015-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Condensed Matter Physics |
| spelling | doaj-art-182f0f5e93a04172a1ba164ba4eeecce2025-02-03T01:29:00ZengWileyAdvances in Condensed Matter Physics1687-81081687-81242015-01-01201510.1155/2015/582734582734Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with PseudogapHao Guo0Yan He1Department of Physics, Southeast University, Nanjing 211189, ChinaCollege of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064, ChinaRecent experimental progress allows for exploring some important physical quantities of ultracold Fermi gases, such as the compressibility, spin susceptibility, viscosity, optical conductivity, and spin diffusivity. Theoretically, these quantities can be evaluated from suitable linear response theories. For BCS superfluid, it has been found that the gauge invariant linear response theories can be fully consistent with some stringent consistency constraints. When the theory is generalized to stronger than BCS regime, one may meet serious difficulties to satisfy the gauge invariance conditions. In this paper, we try to construct density and spin linear response theories which are formally gauge invariant for a Fermi gas undergoing BCS-Bose-Einstein Condensation (BEC) crossover, especially below the superfluid transition temperature Tc. We adapt a particular t-matrix approach which is close to the G0G formalism to incorporate noncondensed pairing in the normal state. We explicitly show that the fundamental constraints imposed by the Ward identities and Q-limit Ward identity are indeed satisfied.http://dx.doi.org/10.1155/2015/582734 |
| spellingShingle | Hao Guo Yan He Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with Pseudogap Advances in Condensed Matter Physics |
| title | Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with Pseudogap |
| title_full | Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with Pseudogap |
| title_fullStr | Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with Pseudogap |
| title_full_unstemmed | Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with Pseudogap |
| title_short | Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with Pseudogap |
| title_sort | theoretical approach to the gauge invariant linear response theories for ultracold fermi gases with pseudogap |
| url | http://dx.doi.org/10.1155/2015/582734 |
| work_keys_str_mv | AT haoguo theoreticalapproachtothegaugeinvariantlinearresponsetheoriesforultracoldfermigaseswithpseudogap AT yanhe theoreticalapproachtothegaugeinvariantlinearresponsetheoriesforultracoldfermigaseswithpseudogap |