Relativistic kinetics of phonon gas in superfluids

Popov, Vladimir

doi:10.1007/s10714-006-0272-7

Cited by 14 publications

(14 citation statements)

References 21 publications

(52 reference statements)

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“…Similar results have been reported in Ref. [17], although implemented in a different manner. The advantage of this formulation is twofold.…”

Section: Discussionsupporting

confidence: 89%

“…In a different frame the dispersion law takes a rather complicated form. In order to express such a relation in a compact way it is convenient to define the following Lorentz invariants [17] …”

Section: B Phonons Moving In the Superfluid Backgroundmentioning

confidence: 99%

“…It is thus natural to expect that the phonons of a relativistic superfluid admit a similar treatment, as we show here. Let us mention that Popov also derived a similar transport equation for the superfluid phonons [17]. We will implement the same ideas in a somewhat different way.…”

Section: Introductionmentioning

confidence: 99%

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Transport theory for cold relativistic superfluids from an analogue model of gravity

Mannarelli

Manuel

2008

Phys. Rev. D

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We write a covariant transport equation for the phonon excitations of a relativistic superfluid valid at small temperatures. The hydrodynamical equations for this system are derived from the effective field theory associated to the superfluid phonons. We describe how to construct the kinetic theory for the phonon quasiparticles using a relativistic generalization of the analogue model of gravity developed by Unruh. This gravity analogy relies on the equivalence between the action of a phonon field moving in a superfluid background with that of a boson propagating in a given curved space-time. Exploiting this analogy we obtain continuity equations for the phonon current, entropy and energy-momentum tensor in a covariant form, valid in any reference frame. Our aim is to shed light on some aspects of transport phenomena of relativistic superfluidity. In particular, we are interested in the low temperature regime of the color flavor locked phase, which is a color superconducting and superfluid phase of high density QCD that may be realized in the core of neutron stars.

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“…Similar results have been reported in Ref. [17], although implemented in a different manner. The advantage of this formulation is twofold.…”

Section: Discussionsupporting

confidence: 89%

Section: B Phonons Moving In the Superfluid Backgroundmentioning

confidence: 99%

See 1 more Smart Citation

Transport theory for cold relativistic superfluids from an analogue model of gravity

Mannarelli

Manuel

2008

Phys. Rev. D

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“…This implies that a formalism based on the dissipative fluxes is structurally perturbative. On the other hand, a theory based on the physical currents n ρ , s ρ and z ρ -which can be also defined arbitrarily far from equilibrium through kinetic theory [31,33] -does not need to make explicit reference of an equilibrium state in the constitutive relations. Clearly, for this hydrodynamic model to have physical significance, in the end one needs to impose a near-equilibrium assumption, but this is implemented only at the level of the initial conditions, not directly into the mathematical structure of the equations.…”

Section: B Advantages Of a Three Currents Formulation à-La Cartermentioning

confidence: 99%

Extending Israel and Stewart hydrodynamics to relativistic superfluids via Carter's multifluid approach

Gavassino,

Antonelli,

Haskell

2021

Preprint

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We construct a relativistic model for bulk viscosity and heat conduction in a superfluid. Building on the principles of Unified Extended Irreversible Thermodynamics, the model is derived from Carter's multifluid approach for a theory with three currents, where the quasi-particle current is an independent hydrodynamic degree of freedom. For small deviations from local thermodynamic equilibrium, the model reduces to an extension of the Israel-Stewart theory to superfluid systems. It can, therefore, be made hyperbolic, causal and stable if the microscopic input is accurate. The non-dissipative limit of the model is the relativistic two-fluid model of Carter, Khalatnikov and Gusakov. The Newtonian limit of the model is an Extended-Irreversible-Thermodynamic extension of Landau's two-fluid model. The model predicts the existence of four bulk viscosity coefficients and accounts for their microscopic origin, providing their exact formulas in terms of the quasi-particle creation rate. Furthermore, when fast oscillations of small amplitude around the equilibrium are considered, the relaxation-time term in the telegraph-type equations for the bulk viscosities accounts directly for their expected dependence on the frequency.

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“…É importante questionar os sujeitos sobre quaisquer dúvidas que eles tenham apresentado durante a aplicação do questionário e o motivo da escolha de cada resposta, para se assegurar de que a versão adaptada ainda mantém a equivalência em situações aplicáveis e pode ser entendida pela população alvo. O estágio final do processo de adaptação é a submissão de todos os relatórios e formulários para o desenvolvedor do instrumento e para o comitê que companha a versão traduzida.Após seguir os estágios acima descritos, de maneira criteriosa, é possível que verificar na versão traduzida, a mesma validade de constructo que o questionário original 64. No entanto esse processo não garante que o instrumento seja válido e confiável na população alvo, e dessa forma, é recomendado que sejam avaliadas as propriedades psicométricas do novo instrumento de avaliação 65.…”

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Adaptação transcultural do Headache Disability Inventory (HDI), validade e confiabilidade do HDI e da versão brasileira do teste do impacto da dor de cabeça (HIT-6TM) em pacientes com cefaleias

Pradela¹

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PRADELA J. Cross-cultural adaptation of the Headache Disability Inventory (HDI), validity and reliability of HDI and the Brazilian version of the Headache Impact Test (HIT-6TM) in patients with headache. [thesis]. Ribeirão Preto: University of São Paulo, Ribeirão Preto Medical School, 2020. 99p. Headache is a symptom frequently reported by patients in clinical practice and it is related to a substantial impact on patients' daily life. However, many patients have difficulties to report pain and disability levels, and these aspects are relevant in the therapeutic approach. The Headache Disability Inventory (HDI) and the Headache Impact Test (HIT-6™) are questionnaires that measure the frequency that the headache interferes in the health and well-being of the individual. However, the HDI is not translated or adapted for the Brazilian population and the HIT-6™ did not have its psychometric properties evaluated so far. Therefore, the aim of this study was to translate and to perform the crosscultural adaptation of the HDI questionnaire into Brazilian Portuguese and to evaluate the validity and reliability of HDI and HIT-6™ headaches. The sample was screened from the Headache Outpatient Clinic of the FMRP/USP with diagnosis of primary and secondary headaches according to the International Classifications of Headaches. Individuals between 18 to 65 years old and headaches at least once within the last month were included. Up to 30 patients (age 34.9; SD 11.5) were included for the cross-cultural adaptation of the HDI questionnaire and, 132 (age: 39.6; DP 12.7) and 67 (age: 36.8; DP:12.5) patients were included for the validity and reliability of the HDI and HIT-6™, respectively. The translated and adapted version of the HDI was administered in 30 patients and only 20% of them had doubts regarding the understanding and meaning of the words. Its internal consistency was 0.84, considered an optimal correlation between the questionnaire items. Thus, the version applied at the pre-test stage was defined as the final version of the questionnaire. The HDI-Brazil questionnaire showed a moderate positive correlation with the HIT-6 TM (0.67, ICC95%: 0.56 to 0.75; p<0.05) and a strong negative correlation with the SF-12 questionnaire (-0.70, ICC95%:-0.79 to-0.59; p<0.05) in the construct validity assessment. HIT-6 TM also showed a moderate negative correlation with the SF-12 questionnaire (-0.64, ICC95%:-0.72 to-0.52; p<0.05). The reliability between first and second evaluations was excellent for both the HDI-Brazil (ICC: 0.95; p<0.05) and for HIT-6 TM (ICC: 0.95; p<0.05). The HDI-Brazil and HIT-6 TM presented a standard measurement error of 2.26 and 0.70, respectively. Therefore, the HDI-Brazil and HIT-6 TM questionnaires were considered valid and reliable for the evaluation of the impact of different types of headache among the Brazilian population.

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Relativistic kinetics of phonon gas in superfluids

Cited by 14 publications

References 21 publications

Transport theory for cold relativistic superfluids from an analogue model of gravity

Transport theory for cold relativistic superfluids from an analogue model of gravity

Extending Israel and Stewart hydrodynamics to relativistic superfluids via Carter's multifluid approach

Adaptação transcultural do Headache Disability Inventory (HDI), validade e confiabilidade do HDI e da versão brasileira do teste do impacto da dor de cabeça (HIT-6TM) em pacientes com cefaleias

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