Estimation of the condensate fraction from the static structure factor
| Autor: | Grigori E. Astrakharchik, Yu. E. Lozovik, Jordi Boronat, I. L. Kurbakov |
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| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. SIMCON - First-principles approaches to condensed matter physics: quantum effects and complexity |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Density matrix
Quantum Monte Carlo Montecarlo Mètode de FOS: Physical sciences 02 engineering and technology Bose-Einstein condensation 01 natural sciences law.invention law 0103 physical sciences Condensació de Bose-Einstein 010306 general physics Physics Mesoscopic physics Física [Àrees temàtiques de la UPC] Superfluïdesa Zero (complex analysis) Superfluid density Bose-Einstein condensates 021001 nanoscience & nanotechnology Quantum Monte-Carlo Monte Carlo method Quantum Gases (cond-mat.quant-gas) Superfluidity Thermodynamic limit Atomic physics Condensed Matter - Quantum Gases 0210 nano-technology Structure factor Bose–Einstein condensate Superfluid helium-4 |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) |
| Popis: | We present an analytical method to estimate the condensate fraction $n_0/n$ in strongly correlated systems for which the zero-temperature static structure factor $S({\bf p})$ is known. The advantage of the proposed method is that it allows one to predict the long-range behavior of the one-body density matrix (i) in macroscopic and mesoscopic systems, (ii) in three- and two-dimensional geometry, (iii) at zero and low finite temperature, and (iv) in weakly and strongly correlated regimes. Our method is tested against exact values obtained with various quantum Monte Carlo methods in a number of strongly correlated systems showing an excellent agreement. The proposed technique is also useful in numerical simulations as it allows one to extrapolate the condensate fraction to the thermodynamic limit for particle numbers as small as tens to hundreds. Our method is especially valuable for extracting the condensate fraction from the experimentally measured static structure factor $S({\bf p})$, thus providing a new simple alternative technique for the estimation of $n_0/n$. We analyze available experimental data for $S({\bf p})$ of superfluid helium and find an excellent agreement with the experimental value of $n_0/n$. Comment: 11 pages, 10 figures, published version |
| Databáze: | OpenAIRE |
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