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.

EFFECT OF HIGHER ORDER ENERGY CORRECTIONS INCLUDING THREE-BODY INTERACTION ON THE BOSE-EINSTEIN CONDENSATE WITH THE VARIATION OF REPULSIVE SELF INTERACTION ENERGY

2006 ◽  
Vol 20 (11n13) ◽  
pp. 1690-1698 ◽  
Author(s):  
SHRI PRAKASH TEWARI ◽  
POONAM SILOTIA ◽  
ADITYA SAXENA ◽  
LOKESH KUMAR GUPTA
Keyword(s):  
Interaction Energy ◽  
Chemical Potential ◽  
Hard Core ◽  
Higher Order ◽  
Einstein Condensate ◽  
Body Interaction ◽  
Interaction Terms ◽  
Bose Einstein Condensate ◽  
Three Body ◽  
Bose Einstein

Various ground state properties such as chemical potential, differential and total energy per particle etc. of Bose-Einstein condensate of 10000 85 Rb atoms with varying repulsive self-interaction energy have been reported considering not only two-body interaction but also including the higher order terms of the low-density energy expansion of homogeneous Bose gas in the Ginzburg, Pitaevskii and Gross (GPG) equation. These include hard-core approximation of the bosons neglected earlier and the three-body interaction terms. The study is more general as it includes the terms beyond logarithm in energy density expansion. It is also shown that such a consideration does not violate the lower bound predicted earlier in which the 'constant' beyond logarithm term in the three-body interaction was neglected.

BOSE-EINSTEIN CONDENSATION OF ATOMS WITH ATTRACTIVE INTERACTION

1999 ◽  
Vol 13 (05n06) ◽  
pp. 625-631 ◽  
Author(s):  
N. AKHMEDIEV ◽  
M. P. DAS ◽  
A. V. VAGOV
Keyword(s):  
Statistical Physics ◽  
Scattering Length ◽  
Stationary Solutions ◽  
Attractive Potential ◽  
Einstein Condensation ◽  
Pitaevskii Equation ◽  
Bose Einstein Condensation ◽  
Three Body ◽  
Negative Scattering Length ◽  
Bose Einstein

We suggest that crucial effect on Bose-Einstein condensation in systems with attractive potential is three-body interaction. We investigate stationary solutions of the Gross-Pitaevskii equation with negative scattering length and a higher-order stabilising term in presence of an external parabolic potential. Stability properties of the condensate are similar to those for thermodynamic systems in statistical physics which have first order phase transitions. We have shown that there are three possible type of stationary solutions corresponding to stable, metastable and unstable phases. Results are discussed in relation to recently observed 7 Li condensate.

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.

scholarly journals Bose–Einstein Condensation for Two Dimensional Bosons in the Gross–Pitaevskii Regime

2021 ◽  
Vol 183 (3) ◽  
Author(s):  
Cristina Caraci ◽  
Serena Cenatiempo ◽  
Benjamin Schlein
Keyword(s):  
Scattering Length ◽  
Low Energy ◽  
Einstein Condensation ◽  
Repulsive Interaction ◽  
Two Dimensional ◽  
Bose Einstein Condensation ◽  
Dimensional Unit ◽  
Optimal Bounds ◽  
Bose Einstein ◽  
Number Of Particles

AbstractWe consider systems of N bosons trapped on the two-dimensional unit torus, in the Gross-Pitaevskii regime, where the scattering length of the repulsive interaction is exponentially small in the number of particles. We show that low-energy states exhibit complete Bose–Einstein condensation, with almost optimal bounds on the number of orthogonal excitations.

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