English
Related papers

Related papers: White dwarfs as test objects of Lorentz violations

200 papers

We clarify the relation between the improvement of dispersion relations in the fermion sector of lattice regularized QCD and the improvement of bulk thermodynamic observables. We show that in the infinite temperature limit the cut-off…

High Energy Physics - Lattice · Physics 2008-11-26 P. Hegde , F. Karsch , E. Laermann , S. Shcheredin

Radio-frequency techniques were used to study ultracold fermions. We observed the absence of mean-field "clock" shifts, the dominant source of systematic error in current atomic clocks based on bosonic atoms. This is a direct consequence of…

We investigate a scale-invariant two-component Fermi gas in a time-dependent isotropic harmonic potential. The exact time evolution of the density distribution in position space in any spatial dimension is obtained. Two experimentally…

Quantum Gases · Physics 2012-07-20 Sergej Moroz

We analyse f(R) modifications of Einstein's gravity as dark energy models in the light of their connection with chameleon theories. Formulated as scalar-tensor theories, the f(R) theories imply the existence of a strong coupling of the…

Astrophysics · Physics 2009-02-23 Philippe Brax , Carsten van de Bruck , Anne-Christine Davis , Douglas J. Shaw

We use the results of ultra-precise cold-atom-recoil experiments to constrain the form of the energy-momentum dispersion relation, a structure that is expected to be modified in several quantum-gravity approaches. Our strategy of analysis…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Giovanni Amelino-Camelia , Claus Laemmerzahl , Flavio Mercati , Guglielmo M. Tino

Motivated by recent experiments on rotating Bose-Einstein condensates, we investigate a rotating, polarized Fermi gas trapped in an anharmonic potential. We apply a semiclassical expansion of the density of states in order to determine how…

Statistical Mechanics · Physics 2015-05-13 Kiel Howe , Aristeu R. P. Lima , Axel Pelster

We relate short-range correlations in ultracold atomic Fermi gases to the entropy of the system over the entire temperature, $T$, vs. coupling strength, $-1/k_Fa$, plane. In the low temperature limit the entropy is dominated by phonon…

Quantum Gases · Physics 2009-08-31 Zhenhua Yu , Georg M. Bruun , Gordon Baym

We study a quantum fermion field inside a cylinder in Minkowski space-time. On the surface of the cylinder, the fermion field satisfies either spectral or MIT bag boundary conditions. We define rigidly-rotating quantum states in both cases,…

High Energy Physics - Theory · Physics 2016-05-18 Victor E. Ambrus , Elizabeth Winstanley

We study the effect of mesoscopic fluctuations on the validity of the Wiedemann--Franz (WF) law for quasi-one-dimensional metal wires and open quantum dots. At temperatures much less than the generalized Thouless energy, E_c, the WF law is…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Maxim G. Vavilov , A. Douglas Stone

The white dwarf luminosity function, which provides information about their cooling, has been measured with high precision in the past few years. Simulations that include well known Standard Model physics give a good fit to the data. This…

High Energy Physics - Phenomenology · Physics 2015-06-15 Herbert K. Dreiner , Jean-François Fortin , Jordi Isern , Lorenzo Ubaldi

Modified gravity theories can introduce modifications to the Poisson equation in the Newtonian limit. As a result, we expect to see interesting features of these modifications inside stellar objects. White dwarf stars are one of the most…

General Relativity and Quantum Cosmology · Physics 2017-10-06 Srimanta Banerjee , Swapnil Shankar , Tejinder P. Singh

If Lorentz and CPT violation exist, they could affect the decays of scalar and pseudoscalar particles. For a decay into a fermion and an antifermion (not necessarily of the same mass), both the total decay rate and the outgoing particle…

High Energy Physics - Phenomenology · Physics 2014-06-11 Brett Altschul

We consider an ultracold gas of (non-condensed) bosons or fermions with two internal states, and study the effect of a gradient of the transition frequency between these states. When a $\pi/2$ RF pulse is applied to the sample, exchange…

Statistical Mechanics · Physics 2009-11-07 J. N. Fuchs , D. M. Gangardt , F. Laloe

We determine the dispersion relations of fermionic quasiparticles in ultradegenerate plasmas by a complete evaluation of the on-shell hard-dense-loop-resummed one-loop fermion self energy for momenta of the order of the Fermi momentum and…

High Energy Physics - Phenomenology · Physics 2009-11-11 A. Gerhold , A. Rebhan

When Lorentz invariance is violated at high energy, the laws of black hole thermodynamics are apparently no longer satisfied. To shed light on this observation, we study dispersive fields in de Sitter space. We show that the Bunch-Davies…

High Energy Physics - Theory · Physics 2012-11-28 Xavier Busch , Renaud Parentani

We have observed condensation of fermionic atom pairs in the BCS-BEC crossover regime. A trapped gas of fermionic 40K atoms is evaporatively cooled to quantum degeneracy and then a magnetic-field Feshbach resonance is used to control the…

Statistical Mechanics · Physics 2009-11-10 C. A. Regal , M. Greiner , D. S. Jin

We consider supersymmetry field theory with supercomponents being the square root of the Bose condensate density, the amplitude of its fluctuations and Grassmannian fields related to the Fermi particles density. The fermion number is…

Statistical Mechanics · Physics 2009-08-04 Alexander Olemskoi , Irina Shuda

This paper focuses on additional inspections concerning the fermionic sector of the Standard Model Extension (SME). In this context, our main effort in this contribution is to investigate effects of Lorentz-symmetry violation (LSV) on the…

High Energy Physics - Phenomenology · Physics 2024-09-17 João Paulo S. Melo , José A. Helayël-Neto

We show that recently proposed white dwarf models with masses well in excess of the Chandrasekhar limit, based on modifying the equation of state by a super-strong magnetic field in the centre, are very far from equilibrium because of the…

Solar and Stellar Astrophysics · Physics 2015-02-10 Rajaram Nityananda , Sushan Konar

In this work, cold and hot, static and rotating white dwarf stars are investigated within the framework of classical physics, employing the Chandrasekhar equation of state. The main parameters of white dwarfs such as the central density,…

Solar and Stellar Astrophysics · Physics 2019-05-20 Kuantay Boshkayev