A geometric interpretation for an algebraic interacting boson-fermion model with configuration mixing is presented. The formalism is based on an extended Bose-Fermi matrix coherent states and is applied to gain insight on intertwined quantum shape-phase transitions and shape coexistence in odd-mass Nb nuclei.

Israel

A. Leviatan

N. Gavrielov

Geometry of configuration mixing in Bose-Fermi systems

The effect of noise induced by gravitons on a Bose-Einstein condensate has been explored in Sen and Gangopadhyay [Probing the quantum nature of gravity using a Bose-Einstein condensate, <a href="http://dx.doi.org/10.1103/PhysRevD.110.026014">Phys. Rev. D 110, 026014 (2024)</a>]. In the previous paper, we investigated the effects of graviton while detecting a gravitational wave using a Bose-Einstein condensate. In this work, we shall explicitly calculate the decoherence due to the noise of gravitons for maximally entangled momentum states of the Bose-Einstein condensate. This decoherence happens due to bremsstrahlung from the Bose-Einstein condensates due to the effect of the noise induced by gravitons. It is observed that the maximally entangled state becomes entangled with the graviton state and it decays over time as a result of this gravitational bremsstrahlung. This new entangled state is termed as a Bose-Einstein supercondensate. Using this property of the Bose-Einstein condensate in a quantum gravity background, we propose an experimental test via the use of atom lasers (generated from the condensate) which would, in principle, help to detect gravitons in future generations of very advanced ultracold temperature experiments.

India

Soham Sen

Sunandan Gangopadhyay

Quantum nature of gravity in a Bose-Einstein condensate

We present recent results in three-flavor chiral perturbation theory at finite isospin <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>μ</mi><mi>I</mi></msub></math> and strangeness <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>μ</mi><mi>S</mi></msub></math> chemical potentials at zero temperature. The tree-level spectrum for the mesons and gauge bosons in the pion-condensed phase is derived. The phase diagram to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mi>p</mi><mn>2</mn></msup><mo stretchy="false">)</mo></math> in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>μ</mi><mi>I</mi></msub><mi>–</mi><msub><mi>μ</mi><mi>S</mi></msub></math> plane is mapped out with and without electromagnetic effects. The phase diagram consists of a vacuum phase and three Bose-condensed phases with condensates of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mo>±</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>±</mo></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mn>0</mn></msup><mo>/</mo><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mn>0</mn></msup></math>, respectively. Including electromagnetic interactions, the charged Bose-condensed phases become Higgs phases via the Higgs mechanism. We calculate the pressure, energy density, isospin density, and speed of sound in the pion-condensed phase to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mi>p</mi><mn>4</mn></msup><mo stretchy="false">)</mo></math>. The results are compared with recent lattice simulations and the agreement is very good for isospin chemical potentials up to approximately 180 MeV. Moreover, by integrating out the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi></math>-quark, we show that the thermodynamic quantities can be mapped onto their two-flavor counterparts with renormalized parameters. The breaking of the U(1) symmetry in the Bose-condensed phases gives rise to a Goldstone boson, whose dispersion is linear for small momenta. We use Son’s prescription to construct an effective theory for the Goldstone mode in the pion-condensed phase, which is valid for momenta <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mo>≪</mo><msub><mi>μ</mi><mi>I</mi></msub></math>. It is shown that its damping rate is of order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>p</mi><mn>5</mn></msup></math> in the nonrelativistic limit, which is Beliaev’s result for a dilute Bose gas. It is also shown that in the nonrelativistic limit the energy density can be matched onto the classic result by Lee, Huang and Yang (LHY) for a dilute Bose, with an <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi></math>-wave scattering length that includes radiative corrections.

Norway

Denmark

Jens O. Andersen

Germany

Martin Kjøllesdal Johnsrud

China

Qing Yu

Hua Zhou

Chiral perturbation theory and Bose-Einstein condensation in QCD

This article presents a new model for anisotropic compact stars that are confined to physical dark matter in the background of <math altimg='si1.svg'><mi>f</mi><mo stretchy='false'>(</mo><mi>T</mi><mo stretchy='false'>)</mo></math> teleparallel gravity. The model is based on the equation of state (EoS) of the bag model type and the Bose-Einstein dark matter density profile. The derived solutions meet the energy conditions, the causality conditions, and the required conditions on the stability factor and adiabatic index, indicating that they are physically well-behaved and represent the physical and stable matter configuration. We also determine the maximum mass, surface redshift, and compactness parameter at the surface. Interestingly, all of these numbers fall within the specified range, supporting the physical viability of our proposal. Additionally, the various masses that are derived for varying the model parameter <italic>k</italic> correspond to five compact, realistic compact objects, including LMC X-4, Her X-1, 4U 1538-52, SAX J1808.4-3658, and Cen X-3. We have also illustrated the radially symmetric profiles of energy density and the moment of inertia for non-rotating stars.

Samprity Das

Prabir Rudra

Surajit Chattopadhyay

Relativistic model of an anisotropic star with Bose-Einstein dark matter density profile in <italic>f</italic>( <italic>T</italic>) gravity

We study the Bose-Einstein condensation (BEC) of a free Bose gas under rigid rotation. The aim is to explore the impact of rotation on the thermodynamic quantities associated with BEC, including the Bose-Einstein (BE) transition temperature and condensate fraction. We begin by introducing the rotation in the Lagrangian density of free charged Klein-Gordon fields and determine the corresponding grand canonical partition function at finite temperature, chemical potential, and finite angular velocity. Assuming slow rotation, we derive analytical expressions for the pressure, energy, number, and angular momentum densities of a free Bose gas in nonrelativistic and ultrarelativistic limits in terms of the corresponding fugacities. We then focus on the phenomenon of BEC. We calculate the critical temperature of BEC transition and the condensate fraction in a slowly rotating Bose gas including only particles. Our findings indicate that the critical exponent associated with the BE transition in a rotating gas is lower compared to that in a nonrotating Bose gas. We also determine the fugacity in a rotating Bose gas in the aforementioned limits and examine how rotation affects its temperature dependence, both below and above the critical temperature. By analyzing the behavior of heat capacity at these temperatures, we demonstrate that in a nonrelativistic Bose gas, the rotation transforms the nature of the BE phase transition from a continuous to a discontinuous transition. In general, we find that a nonrelativistic Bose gas under rotation behaves similarly to a nonrotating Bose gas in ultrarelativistic limit.

Iran

E. Siri

N. Sadooghi

Bose-Einstein condensation in a rigidly rotating relativistic boson gas

We systematically investigate the effects of quantum gravity on the ground-state properties of dilute homogeneous dipolar Bose gases using the Hartree-Fock-Bogoliubov theory based on the generalized uncertainty principle. We calculate quantum gravity corrections to the condensed fraction, the equation of state, the critical temperature and the superfluid fraction. Improved upper bounds on the generalized uncertainty principle parameters are found. We compare our predictions with previous experimental and theoretical results.

Algeria

Asma Tahar Taiba

Abdelâali Boudjemâa

Testing quantum gravity with dilute dipolar Bose gases

We consider resurgence for the nonconformal Bjorken flow with Fermi-Dirac and Bose-Einstein statistics in the extended relaxation-time approximation. First, we examine the full formal transseries expanded around the equilibrium and then construct the resurgent relation by looking at the structure of Borel-transformed ordinary differential equations. We form a conjecture of the resurgent relation based on the consideration that the Stokes constants constituting the resurgent relation originate only from singularities of dissipative variables on the Borel plane and that the other variables such as temperature and chemical potential become Borel nonsummable through nonlinear terms with the dissipative variables. We numerically check the conjecture for fundamental variables by explicitly evaluating the values of the dominant Stokes constant depending on the initial conditions and the particle mass. We also comment on some issues related to transseries structure and resurgence, such as the case of broken U(1) symmetry, the massless case, generalized relaxation time, and attractor solutions.

Poland

Japan

Syo Kamata

Resurgence for the nonconformal Bjorken flow with Fermi-Dirac and Bose-Einstein statistics

During the cosmic evolution process, as the temperature of a cosmological boson gas falls below a certain threshold, a Bose–Einstein condensation process can occur at various points throughout the cosmic history of the Universe. In this model, dark matter, conceptualized as a non-relativistic, Newtonian gravitational condensate is governed by the Gross–Pitaevskii–Poisson system. In our present study, we investigate the Bose–Einstein condensation process of bosonic DM by treating it as an approximate first-order phase transition within a modified cosmological framework, known as Tsallis cosmology. We examine the evolution of relevant physical quantities characterizing the evolution dynamics of the Universe, including energy density, temperature, redshift, scale factor, Hubble parameter, and dimensionless deceleration parameter before, during, and following the Bose–Einstein condensation phase transition takes place. Additionally, we especially investigate the specific era of the evolution of the Universe characterized by a mixture of normal and condensate phases of dark matter. We analyze the behavior of temporal evolution of an important time-dependent parameter, called the condensate dark matter fraction throughout the condensation process and find the time duration of condensation of dark matter in the Tsallis cosmological model. We see that the presence of Bose–Einstein condensate dark matter in the framework of Tsallis-modified cosmology significantly alters the cosmological evolution of the Universe as compared to the standard model of cosmology. We also find for a typical value of Tsallis non-extensive parameter $$\beta =0.35$$ <math> <mrow> <mi>β</mi> <mo>=</mo> <mn>0.35</mn> </mrow> </math> , the model could explain an accelerated Universe without invoking any additional energy component and solve the age problem of our Universe.

Subhra Mondal

Amitava Choudhuri

Dynamics of cosmological phase crossover during Bose–Einstein condensation of dark matter in Tsallis cosmology

A Bose star passing through cold molecular clouds may capture atoms, molecules, and dust particles. The observational signature of such an event would be a relatively small amount of matter that is gravitationally bound. This binding may actually be provided by invisible dark matter forming the Bose star. We may expect a relative excess of heavier atoms, molecules, and solid dust compared to the content of giant cold molecular clouds since the velocity of heavy particles at a given temperature is lower and it may be small compared to the escape velocity, <math><msub><mi>v</mi><mi>rms</mi></msub><mo>=</mo><msqrt><mrow><mn>3</mn><msub><mi>k</mi><mi>B</mi></msub><mi>T</mi><mo>/</mo><msub><mi>m</mi><mi>gas</mi></msub></mrow></msqrt><mo>≪</mo><msub><mi>v</mi><mi>esc</mi></msub><mo>=</mo><msqrt><mrow><mn>2</mn><mi>G</mi><mi>M</mi><mo>/</mo><mi>R</mi></mrow></msqrt></math>. Finally, the velocity of this captured matter cloud may correlate with the expected velocity of free dark matter particles (e.g., expected axion wind velocity relative to Earth).

Australia

V. V. Flambaum

I. B. Samsonov

Captured molecules could make a Bose star visible

One method for determining the characteristic parameters of a hadron production source is to measure the Bose-Einstein correlation functions. In this study, we present fundamental concepts and formulas related to the Bose-Einstein correlations, focusing on the measurement principles and the Lund model from an experimental perspective. We perform Monte Carlo simulations using the Lund model generator in the 2–3 GeV energy range. Through these feasibility studies, we identify key features of the Bose-Einstein correlations that offer valuable insights for experimental measurements. Utilizing data samples collected at BESIII, we perform measurements of the Bose-Einstein correlation functions, with an expected experimental precision of a few percent for the hadron source radius and incoherence parameter.

Hai-Ming Hu

Guang-Shun Huang

Principles and prospects of Bose-Einstein correlation study at BESIII  