Equivalence of the channel-corrected-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>T</mml:mi></mml:math>-matrix and anomalous-propagator approaches to condensation

Morawetz, Klaus

doi:10.1103/physrevb.82.092501

Cited by 7 publications

(6 citation statements)

References 20 publications

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“…The GF approximation satisfies both Baym-Kadanoff conditions. 41 The triplet channel in our theory is the same as in the GF theory, and therefore satisfies (23)(24) and (25). We thus focus on the singlet channel in which the RSC theory differs from the GF approximation.…”

Section: B Two-particle Green Functionmentioning

confidence: 99%

“…Though conditions (23)(24)(25)(26) provide in the equilibrium case only limited indication of the validity of full conservation laws, it is significant that the RSC theory passes this test; one can easily show that the other theories we have mentioned fail to satisfy the BK conditions even in equilibrium. For example, the KM approximation does not satisfy the Baym-Kadanoff criterion (26).…”

Section: A Baym-kadanoff Conditionsmentioning

confidence: 99%

“…Substituting ( 27) into (23) and (24) one may check that both formulae yield the singlet self-energy given by relations (1), ( 7) and (10).…”

Section: B Two-particle Green Functionmentioning

confidence: 99%

“…Recent theoretical approaches to superconductivity range from the trial wave functions of Gutzwiller type 14 , over improved Eliashberg theories 15 , renormalization group approaches within path integrals 16 , exact diagonalizations and quantum Monte Carlo studies 17 on simple models having small size or infinite dimensions 18 , to the many-body T-matrix approximations [19][20][21][22][23][24][25] and hybrid theories combining the anomalous functions of Eliashberg type either with the many-body T-matrix 26,27 or with the fluctuation-exchange approximation [28][29][30] .…”

Section: Introductionmentioning

confidence: 99%

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Conserving T-matrix theory of superconductivity

Šopík,

Lipavský,

Männel

et al. 2009

Preprint

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Using principles of the Fadeev-Lovelace-Watson multiple scattering expansion, a T-matrix approximation is derived which coincides with the Galitskii-Feynman T-matrix in the normal state, and yields the gap in the superconducting state. Unlike other T-matrix approaches, the theory satisfies not only the self-consistent Thouless criterion but also the Baym-Kadanoff conditions for a conserving theory in equilibrium. In single-mode approximation it simplifies to the Eliashberg theory.

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Section: B Two-particle Green Functionmentioning

confidence: 99%

Section: A Baym-kadanoff Conditionsmentioning

confidence: 99%

“…Substituting ( 27) into (23) and (24) one may check that both formulae yield the singlet self-energy given by relations (1), ( 7) and (10).…”

Section: B Two-particle Green Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Conserving T-matrix theory of superconductivity

Šopík,

Lipavský,

Männel

et al. 2009

Preprint

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“…Recently it has been shown that one can arrive at the same equations by a completely conserving theory of multiple corrected T‐matrix [ 56–58 ] with equivalent results. [ 59,60 ] This illustrates that the anomalous propagators are a theoretical shortcut to the right result through adopting inconsistent propagators.…”

Section: Introductionmentioning

confidence: 99%

Exploring Anomalies by Many‐Body Correlations

Morawetz

2021

Physica Status Solidi (b)

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The quantum anomaly is written alternatively into a form violating conservation laws or as non‐gauge invariant currents seen explicitly on the example of chiral anomaly. By reinterpreting the many‐body averaging, the connection to Pauli–Villars regularization is established which gives the anomalous term a new interpretation as arising from quantum fluctuations by many‐body correlations at short distances. This is exemplified using an effective many‐body quantum potential which realizes quantum Slater sums by classical calculations. It is shown that these quantum potentials avoid the quantum anomaly but approach the same anomalous result by many‐body correlations. Consequently, quantum anomalies might be a shortcut way of single‐particle field theory to account for many‐body effects. This conjecture is also supported since the chiral anomaly can be derived by a completely conserving quantum kinetic theory. A measure for the quality of quantum potentials is suggested to describe these quantum fluctuations in the mean energy. The derived quantum potentials might be used to describe quantum simulations in classical terms.

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Coexistence of phase transitions and hysteresis near the onset of Bose-Einstein condensation

2013

Self Cite

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Multiple phases occurring in a Bose gas with finite-range interaction are investigated. In the vicinity of the onset of Bose-Einstein condensation (BEC) the chemical potential and the pressure show a van-der-Waals like behavior indicating a first-order phase transition although there is no longrange attraction. Furthermore the equation of state becomes multivalued near the BEC transition. For a Hartree-Fock or Popov (Hartree-Fock-Bogoliubov) approximation such a multivalued region can be avoided by the Maxwell construction. For sufficiently weak interaction the multivalued region can also be removed using a many-body T-matrix approximation. However, for strong interactions there remains a multivalued region even for the T-matrix approximation and after the Maxwell construction, what is interpreted as a density hysteresis. This unified treatment of normal and condensed phases becomes possible due to the recently found scheme to eliminate self-interaction in the T-matrix approximation, which allows to calculate properties below and above the critical temperature.PACS numbers: 03.75.-b, 67.85.-d

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Equivalence of the channel-corrected-T-matrix and anomalous-propagator approaches to condensation

Cited by 7 publications

References 20 publications

Conserving T-matrix theory of superconductivity

Conserving T-matrix theory of superconductivity

Exploring Anomalies by Many‐Body Correlations

Coexistence of phase transitions and hysteresis near the onset of Bose-Einstein condensation

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