Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

CRC Press eBooks

Bose–Einstein condensation

Kerson Huang

Published Nov 9, 2001• 177 citations
Publisher

Abstract

Consider a gas of bosons whose total number is conserved. The equation for the fugacity is nλ3 = g3/2(z) (11.1) and a qualitative plot of the function g3/2 is shown in Fig.11. 1. The function has infinite slope at z = 1, since z d dz g3/2(z) = g1/2(z) = ∞∑ =1 z√ (11.2) and the series diverges at z = 1. It is thus bounded by the value g3/2(1) = ∞∑ =1 −3/2 = ζ (3/2) = 2.612 . . . (11.3) solution to (11.1) nλ3 ≤ g3/2(1). (11.4) This condition can be violated by increasing the density, or lowering the temperature. What then would be the value of z?

DOI
10.1201/9781482268300-13

Related papers

Bose–Einstein Condensation

Kerson Huang

This condition can be violated by increasing the density, or lowering the temperature. What then would be the value of z ? To answer this question, recall that in deriving Equation (18.1) in Section 14.12, we took the infinite-volume limit, and replaced the sum over states by an integration. This assigns zero weight to the state of zero momentum, for the volume element 4πp2dp vanishes at p = 0. In the formula (Equation [18.1]), n is therefore the density of particles with nonzero momentum, and this is the quantity bounded by Equation (18.4). When this bound is exceeded, the excess particles cannot disappear, as photons could, because their number is conserved. They are forced to go into the zero-momentum state, and this single quantum state becomes macroscopically occupied, that is, occupied by a finite fraction of the particles. This phenomenon is called Bose-Einstein condensation.

Chapman & Hall/CRC eBooks•Sep 21, 2009•7 citations

The Perfect Bose Gas: Bose-Einstein Condensation

Jeffrey Olafsen

This chapter focuses on integrating the distribution function over all the states of conserved Bosons to obtain a relation between particle density and the chemical potential. It describes the phenomenon of Bose-Einstein condensation in a perfect boson gas. The chapter discusses the experimental observation of Bose-Einstein condensation in perfect gases. There are two routes to obtaining Bose-Einstein condensation in a perfect gas. One is to reduce the mass of the particle, thus reducing critical density to a low value at a reasonable temperature. The other route is to lower the temperature to the point where the critical density is so low that the particles are too far apart to interact with each other.

CRC Press eBooks•Jul 26, 2019•0 citations

The Perfect Bose Gas: Bose-Einstein Condensation

Michael D. Sturge

We now turn to the other type of boson: a particle, such as an atom or molecule, with integer or zero spin, whose number is conserved. As in the case of the ideal gas, we integrate the distribution function over all the states to obtain a relation between particle density n and the chemical potential . The density is, from Equation (8.4), n = g(E)f(E) dE where, from Equation (8.10), f(E) = 1 e#(E ) 1 .

A K Peters/CRC Press eBooks•Oct 8, 2018•0 citations

Approaching Bose–Einstein condensation

L. Ferrari

Bose–Einstein condensation (BEC) is discussed at the level of an advanced course of statistical thermodynamics, clarifying some formal and physical aspects that are usually not covered by the standard pedagogical literature. The non-conventional approach adopted starts by showing that the continuum limit, in certain cases, cancels out the crucial role of the bosonic ground level. If so, a correct treatment of the problem, including the ground level population N 0 by construction, leads to BEC in a straightforward way. For a density of states of the form G ( )∝ γ , the chemical potential µ is explicitly calculated as a function of the temperature T and of the number N of bosons, for various significant values of the positive exponent γ. In the thermodynamic limit, in which the boson number N diverges and BEC is a sharp process, the chemical potential µ is a singular function of T at the critical temperature T B , determined by an appropriate critical exponent. The condensate population N 0 is studied analytically and numerically as a function of the temperature, for various values of N and for different γ. This provides an accurate description of the way BEC approaches the character of a sharp phase transition. Some aspects of the real experiments on BEC, involving a finite number of bosons, are also illustrated.

European Journal of Physics•Oct 4, 2011•5 citations

Bose–Einstein Condensation and the Debye Law The Density of States Chooses the Zeta Argument, the Pole Decides

Thomas Krause

For an ideal Bose gas whose density of states grows like εᵃ⁻¹, every equilibrium quantity at the condensation point is a Mellin moment Γ(a)ζ(a) or Γ(a+1)ζ(a+1). The exponent is a = d/2 + d/δ for a gas in d dimensions in a potential r^δ: a = 3/2 in a box, a = 3 in a harmonic trap. We make the arithmetic content of this classical rule explicit. The density of states chooses the zeta argument, and the only pole of ζ, at s = 1, decides three things. Condensation occurs if and only if a > 1, because Liₐ(1) = ζ(a) is finite. The heat capacity jumps at T_c if and only if a > 2, by a²ζ(a)/ζ(a−1), because ζ(a−1) is finite; the value below T_c is a(a+1)ζ(a+1)/ζ(a). In the borderline case a = 1, the one-dimensional harmonic trap, the pole turns into a logarithm: the excited-state sum is the Lambert series Σ d(n)e^(−n/t) of the divisor function with Mellin transform Γ(s)ζ(s)², and its double pole gives t(log t + γ) + 1/4 − 1/(144t) + …, with 1/4 = ζ(0)² and 1/144 = ζ(−1)². The finite-size shift −ζ(2)/(2ζ(3)^(2/3)) · N^(−1/3) of a three-dimensional trap is the next residue of the same kind of transform. Fermions never condense, because η(s) has no pole. The Debye law belongs to the same scheme with an even argument: 12π⁴/5 = 216 ζ(4), and its T³ form is exact at low temperature with the directional average of Σᵢ cᵢ⁻³ over the three sound branches. For copper at 0 K the elastic constants give Θ_D = 344.4 K against the calorimetric 343 K, an independent test of the prefactor at the level of one per cent. The value ζ(3/2) of the box has no known closed form. We also record that the first condensates of 1995 were made in harmonic traps and so test ζ(3), not ζ(3/2). Accompanying code repository contents (SHA256SUMS): a14986048687f94245c87d98670266179a8671cbeeae4af368a675388f778ede README.mdd685a7bcfe008d42d08d4f1546809ddfba3a5bcd4244a92b905b8f7e0ca76c6f p4_checks.py67eca726ed7311cedaf292189e4c55a6cc1c8ca54763ed2e91359617050a4660 p4_checks.log1be23f68b50ea329f2e74db39924ccc60902b3c2db149b921af8d2995fd304ca run_all_checks.py63de8f343011fd3c5e921f67371a96630a5b4ccfaf4194877fd10d963276da61 run_all_checks.log

•Oct 16, 2026•0 citations

Finite-size scaling behavior of Bose-Einstein condensation in the 1D Bose gas

Jun Sato, Eriko Kaminishi, Tetsuo Deguchi

Through exact numerical solutions we show Bose-Einstein condensation (BEC) for the one-dimensional (1D) bosons with repulsive short-range interactions at zero temperature by taking a particular large size limit. Following the Penrose-Onsager criterion of BEC, we define condensate fraction by the fraction of the largest eigenvalue of the one-particle reduced density matrix. % We show the finite-size scaling behavior such that condensate fraction is given by a scaling function of one-variable: interaction parameter multiplied by a power of particle number. Condensate fraction is nonzero and constant for any large value of particle number or system size, if the interaction parameter is proportional to the negative power of particle number. %Here the interaction parameter is defined by the coupling constant of the delta-function potentials devided by the density. %With the scaling behavior we derive various themodynamic limits where condensate fraction is constant for any large system size; for instance, it is the case even in the system of a finite particle number.

arXiv:1303.2775•Mar 12, 2013•2 citations
Consider a gas of bosons whose total number is conserved. The equation for the fugacity is nλ3 = g3/2(z) (11.1) and a qualitative plot of the function g3/2 is shown in Fig.11. 1. The function has infinite slope at z = 1, since z d dz g3/2(z) = g1/2(z) = ∞∑ =1 z√ (11.2) and the series diverges at z = 1. It is thus bounded by the value g3/2(1) = ∞∑ =1 −3/2 = ζ (3/2) = 2.612 . . . (11.3) solution to (11.1) nλ3 ≤ g3/2(1). (11.4) This condition can be violated by increasing the density, or lowering the temperature. What then would be the value of z?
This condition can be violated by increasing the density, or lowering the temperature. What then would be the value of z ? To answer this question, recall that in deriving Equation (18.1) in Section 14.12, we took the infinite-volume limit, and replaced the sum over states by an integration. This assigns zero weight to the state of zero momentum, for the volume element 4πp2dp vanishes at p = 0. In the formula (Equation [18.1]), n is therefore the density of particles with nonzero momentum, and this is the quantity bounded by Equation (18.4). When this bound is exceeded, the excess particles cannot disappear, as photons could, because their number is conserved. They are forced to go into the zero-momentum state, and this single quantum state becomes macroscopically occupied, that is, occupied by a finite fraction of the particles. This phenomenon is called Bose-Einstein condensation.
This chapter focuses on integrating the distribution function over all the states of conserved Bosons to obtain a relation between particle density and the chemical potential. It describes the phenomenon of Bose-Einstein condensation in a perfect boson gas. The chapter discusses the experimental observation of Bose-Einstein condensation in perfect gases. There are two routes to obtaining Bose-Einstein condensation in a perfect gas. One is to reduce the mass of the particle, thus reducing critical density to a low value at a reasonable temperature. The other route is to lower the temperature to the point where the critical density is so low that the particles are too far apart to interact with each other.
Bose–Einstein condensation (BEC) is discussed at the level of an advanced course of statistical thermodynamics, clarifying some formal and physical aspects that are usually not covered by the standard pedagogical literature. The non-conventional approach adopted starts by showing that the continuum limit, in certain cases, cancels out the crucial role of the bosonic ground level. If so, a correct treatment of the problem, including the ground level population N 0 by construction, leads to BEC in a straightforward way. For a density of states of the form G ( )∝ γ , the chemical potential µ is explicitly calculated as a function of the temperature T and of the number N of bosons, for various significant values of the positive exponent γ. In the thermodynamic limit, in which the boson number N diverges and BEC is a sharp process, the chemical potential µ is a singular function of T at the critical temperature T B , determined by an appropriate critical exponent. The condensate population N 0 is studied analytically and numerically as a function of the temperature, for various values of N and for different γ. This provides an accurate description of the way BEC approaches the character of a sharp phase transition. Some aspects of the real experiments on BEC, involving a finite number of bosons, are also illustrated.
For an ideal Bose gas whose density of states grows like εᵃ⁻¹, every equilibrium quantity at the condensation point is a Mellin moment Γ(a)ζ(a) or Γ(a+1)ζ(a+1). The exponent is a = d/2 + d/δ for a gas in d dimensions in a potential r^δ: a = 3/2 in a box, a = 3 in a harmonic trap. We make the arithmetic content of this classical rule explicit. The density of states chooses the zeta argument, and the only pole of ζ, at s = 1, decides three things. Condensation occurs if and only if a > 1, because Liₐ(1) = ζ(a) is finite. The heat capacity jumps at T_c if and only if a > 2, by a²ζ(a)/ζ(a−1), because ζ(a−1) is finite; the value below T_c is a(a+1)ζ(a+1)/ζ(a). In the borderline case a = 1, the one-dimensional harmonic trap, the pole turns into a logarithm: the excited-state sum is the Lambert series Σ d(n)e^(−n/t) of the divisor function with Mellin transform Γ(s)ζ(s)², and its double pole gives t(log t + γ) + 1/4 − 1/(144t) + …, with 1/4 = ζ(0)² and 1/144 = ζ(−1)². The finite-size shift −ζ(2)/(2ζ(3)^(2/3)) · N^(−1/3) of a three-dimensional trap is the next residue of the same kind of transform. Fermions never condense, because η(s) has no pole. The Debye law belongs to the same scheme with an even argument: 12π⁴/5 = 216 ζ(4), and its T³ form is exact at low temperature with the directional average of Σᵢ cᵢ⁻³ over the three sound branches. For copper at 0 K the elastic constants give Θ_D = 344.4 K against the calorimetric 343 K, an independent test of the prefactor at the level of one per cent. The value ζ(3/2) of the box has no known closed form. We also record that the first condensates of 1995 were made in harmonic traps and so test ζ(3), not ζ(3/2). Accompanying code repository contents (SHA256SUMS): a14986048687f94245c87d98670266179a8671cbeeae4af368a675388f778ede README.mdd685a7bcfe008d42d08d4f1546809ddfba3a5bcd4244a92b905b8f7e0ca76c6f p4_checks.py67eca726ed7311cedaf292189e4c55a6cc1c8ca54763ed2e91359617050a4660 p4_checks.log1be23f68b50ea329f2e74db39924ccc60902b3c2db149b921af8d2995fd304ca run_all_checks.py63de8f343011fd3c5e921f67371a96630a5b4ccfaf4194877fd10d963276da61 run_all_checks.log
Through exact numerical solutions we show Bose-Einstein condensation (BEC) for the one-dimensional (1D) bosons with repulsive short-range interactions at zero temperature by taking a particular large size limit. Following the Penrose-Onsager criterion of BEC, we define condensate fraction by the fraction of the largest eigenvalue of the one-particle reduced density matrix. % We show the finite-size scaling behavior such that condensate fraction is given by a scaling function of one-variable: interaction parameter multiplied by a power of particle number. Condensate fraction is nonzero and constant for any large value of particle number or system size, if the interaction parameter is proportional to the negative power of particle number. %Here the interaction parameter is defined by the coupling constant of the delta-function potentials devided by the density. %With the scaling behavior we derive various themodynamic limits where condensate fraction is constant for any large system size; for instance, it is the case even in the system of a finite particle number.