scholarly journals Black holes as gases of punctures with a chemical potential: Bose-Einstein condensation and logarithmic corrections to the entropy

2015 ◽  
Vol 91 (8) ◽  
Author(s):  
Olivier Asin ◽  
Jibril Ben Achour ◽  
Marc Geiller ◽  
Karim Noui ◽  
Alejandro Perez
Keyword(s):  
Black Holes ◽  
Chemical Potential ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Logarithmic Corrections ◽  
Bose Einstein

scholarly journals Evidence for spin current driven Bose-Einstein condensation of magnons

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
B. Divinskiy ◽  
H. Merbouche ◽  
V. E. Demidov ◽  
K. O. Nikolaev ◽  
L. Soumah ◽  
...  
Keyword(s):  
Room Temperature ◽  
Chemical Potential ◽  
Spin Current ◽  
Einstein Condensation ◽  
Electronic Control ◽  
Spintronic Devices ◽  
Bose Einstein Condensation ◽  
Magnetic Insulators ◽  
Spatially Extended ◽  
Bose Einstein

AbstractThe quanta of magnetic excitations – magnons – are known for their unique ability to undergo Bose-Einstein condensation at room temperature. This fascinating phenomenon reveals itself as a spontaneous formation of a coherent state under the influence of incoherent stimuli. Spin currents have been predicted to offer electronic control of Bose-Einstein condensates, but this phenomenon has not been experimentally evidenced up to now. Here we show that current-driven Bose-Einstein condensation can be achieved in nanometer-thick films of magnetic insulators with tailored nonlinearities and minimized magnon interactions. We demonstrate that, above a certain threshold, magnons injected by the spin current overpopulate the lowest-energy level forming a highly coherent spatially extended state. We quantify the chemical potential of the driven magnon gas and show that, at the critical current, it reaches the energy of the lowest magnon level. Our results pave the way for implementation of integrated microscopic quantum magnonic and spintronic devices.

scholarly journals Bose-Einstein Condensation of Confined Atomic Gases at Ultra Low Temperatures

2017 ◽  
Vol 9 (5) ◽  
pp. 96
Author(s):  
M. Serhan
Keyword(s):  
Low Temperatures ◽  
Chemical Potential ◽  
Scattering Length ◽  
Einstein Condensation ◽  
Pitaevskii Equation ◽  
Atomic Gases ◽  
Bose Einstein Condensation ◽  
Gaussian Type ◽  
Negative Scattering Length ◽  
Bose Einstein

In this work I solve the Gross-Pitaevskii equation describing an atomic gas confined in an isotropic harmonic trap by introducing a variational wavefunction of Gaussian type. The chemical potential of the system is calculated and the solutions are discussed in the weakly and strongly interacting regimes. For the attractive system with negative scattering length the maximum number of atoms that can be put in the condensate without collapse begins is calculated.

scholarly journals Particle number fluctuations in a non-ideal pion gas

2018 ◽  
Vol 182 ◽  
pp. 02066
Author(s):  
Evgeni E. Kolomeitsev ◽  
Maxim E. Borisov ◽  
Dmitry N. Voskresensky
Keyword(s):  
Critical Point ◽  
Particle Number ◽  
Chemical Potential ◽  
Pion Mass ◽  
Thermodynamic Characteristics ◽  
Ideal Gas ◽  
Fixed Number ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Bose Einstein

We consider a non-ideal hot pion gas with the dynamically fixed number of particles in the model with the λφ4 interaction. The effective Lagrangian for the description of such a system is obtained by dropping the terms responsible for the change of the total particle number. Within the self-consistent Hartree approximation, we compute the effective pion mass, thermodynamic characteristics of the system and identify a critical point of the induced Bose-Einstein condensation when the pion chemical potential reaches the value of the effective pion mass. The normalized variance, skewness, and kurtosis of the particle number distributions are calculated. We demonstrate that all these characteristics remain finite at the critical point of the Bose-Einstein condensation. This is due to the non-perturbative account of the interaction and is in contrast to the ideal-gas case.

Bose–Einstein condensation of spin wave quanta at room temperature

2011 ◽  
Vol 369 (1951) ◽  
pp. 3575-3587 ◽  
Author(s):  
O. Dzyapko ◽  
V. E. Demidov ◽  
G. A. Melkov ◽  
S. O. Demokritov
Keyword(s):  
Room Temperature ◽  
Chemical Potential ◽  
Spin Waves ◽  
Einstein Condensation ◽  
Quasi Equilibrium ◽  
Magnetic Media ◽  
Bose Einstein Condensation ◽  
Garnet Films ◽  
Iron Garnet ◽  
Bose Einstein

Spin waves are delocalized excitations of magnetic media that mainly determine their magnetic dynamics and thermodynamics at temperatures far below the critical one. The quantum-mechanical counterparts of spin waves are magnons, which can be considered as a gas of weakly interacting bosonic quasi-particles. Here, we discuss the room-temperature kinetics and thermodynamics of the magnon gas in yttrium iron garnet films driven by parametric microwave pumping. We show that for high enough pumping powers, the thermalization of the driven gas results in a quasi-equilibrium state described by Bose–Einstein statistics with a non-zero chemical potential. Further increases of the pumping power cause a Bose–Einstein condensation documented by an observation of the magnon accumulation at the lowest energy level. Using the sensitivity of the Brillouin light scattering spectroscopy to the degree of coherence of the scattering magnons, we confirm the spontaneous emergence of coherence of the magnons accumulated at the bottom of the spectrum, occurring if their density exceeds a critical value.

Quantum statistics

Quantum 20/20 ◽  
2019 ◽  
pp. 37-54
Author(s):  
Ian R. Kenyon
Keyword(s):  
Chemical Potential ◽  
Quantum Statistics ◽  
Exclusion Principle ◽  
Einstein Condensation ◽  
Exchange Force ◽  
Stellar Objects ◽  
Bose Einstein Condensation ◽  
Boson Exchange ◽  
Degeneracy Pressure ◽  
Bose Einstein

Indistinguishability of like particles, and the fermion and boson exchange symmetries discussed.Pauli exclusion principle and features of multi-electron atoms, including selection rules are discussed. Degeneracy pressure and the formation of compact stellar objects is analysed. Quantum exchange force between electrons and its contribution to ferromagnetism is outlined. Fermi-Dirac and Bose-Einstein statistics, includng the chemical potential are derived. The conditions for Bose-Einstein condensation are deduced; condensates and their stability are considered.

Detailed investigation of dynamic of Bose–Einstein condensation with two, three body and higher-order interactions

2021 ◽  
Vol 35 (06) ◽  
pp. 2150088
Author(s):  
Neslihan Üzar
Keyword(s):  
Chemical Potential ◽  
Higher Order ◽  
Binary Interaction ◽  
Einstein Condensation ◽  
Repulsive Interaction ◽  
Bose Einstein Condensation ◽  
Body Interaction ◽  
Interaction Types ◽  
Three Body ◽  
Bose Einstein

In this study, we investigate the effects of three body and higher-order interactions (HOIs) with two-body interaction on ground state properties of Bose–Einstein condensation (BEC) for combined optical and harmonic potentials in detail by solving new modified Gross–Pitaevskii equation (GPE). In fact, the basis of the study is combinations of attractive and repulsive two-body interaction with other attractive and repulsive interaction types. The obtained results show that taking into account higher order and three-body interactions collectively support to stabilize the BEC system regardless of repulsive or attractive two-body interaction. When repulsive (attractive) binary interaction exists in the system, having at least one attractive (repulsive) interaction type makes the system stable. Also, the stability of the BEC system is discussed by the calculating energy. The energy of the system is determined by semi-analytical approach. Finally, the chemical potential of system is calculated according to different possible combined interaction types. It is observed that generally, the sign of the chemical potential is determined by sign of the strongest interaction in the system, especially three-body interaction. Detailed results are given in this paper.

Thermodynamics

2017 ◽  
Author(s):  
Nicholas Manton ◽  
Nicholas Mee
Keyword(s):  
Chemical Potential ◽  
Black Body ◽  
Black Body Radiation ◽  
Spin Systems ◽  
Atomic Scale ◽  
Einstein Condensation ◽  
Maxwell Distribution ◽  
Bose Einstein Condensation ◽  
Thermodynamic Variables ◽  
Bose Einstein

This chapter is about thermodynamics, or statistical mechanics, which explains macroscopic features of the world in terms of the motion of vast numbers of particles on the atomic scale. It discusses how macroscopic variables such as temperature and entropy were originally introduced, before presenting modern definitions of temperatures and entropy and the Laws of Thermodynamics. Alternative thermodynamic variables, including enthalpy and the Gibbs free energy, are defined and the Gibbs distribution is explained. The Maxwell distribution is derived. The chemical potential is introduced and the pressure and heat capacity of an electron gas is calculated, The Fermi–Dirac and Bose–Einstein functions are derived. Bose–Einstein condensation is explained. Black body radiation is discussed and the Planck formula is derived. Lasers are explained. Spin systems are used to model magnetization. Phase transitions are briefly discussed. Hawking radiation and the thermodynamics of black holes is explained.

scholarly journals STRING PICTURE OF BOSE–EINSTEIN CONDENSATION

1999 ◽  
Vol 13 (11) ◽  
pp. 349-362 ◽  
Author(s):  
S. BUND ◽  
A. M. J. SCHAKEL
Keyword(s):  
Chemical Potential ◽  
Canonical Ensemble ◽  
String Tension ◽  
Einstein Condensation ◽  
Winding Number ◽  
Imaginary Time ◽  
Bose Einstein Condensation ◽  
Bose Einstein ◽  
Grand Canonical ◽  
Number Of Particles

A nonrelativistic Bose gas is represented as a grand-canonical ensemble of fluctuating closed spacetime strings of arbitrary shape and length. The loops are characterized by their string tension and the number of times they wind around the imaginary time axis. At the temperature where Bose–Einstein condensation sets in, the string tension, being determined by the chemical potential, vanishes and the strings proliferate. A comparison with Feynman's description in terms of rings of cyclicly permuted bosons shows that the winding number of a loop corresponds to the number of particles contained in a ring.

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