Momentum distribution of liquid helium

Journal Article · Wed Jan 01 04:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.55.1040· OSTI ID:475288

Moroni, S ^[1]; Senatore, G ^[2]; Fantoni, S ^[1]

---

1. International Centre for Theoretical Physics, I-34014, Trieste (Italy)
2. Istituto Nazionale di Fisica della Materia

We have obtained the one-body density matrix and the momentum distribution n(p) of liquid {sup 4}He at T=0 K from diffusion Monte Carlo (DMC) simulations, using trial functions optimized via the Euler Monte Carlo (EMC) method. We find a condensate fraction smaller than in previous calculations. Though we do not explicitly include long-range correlations in our calculations, we obtain a momentum distribution at long wavelength which is compatible with the presence of long-range correlations in the exact wave function. We have also studied {sup 3}He, using fixed-node DMC, with nodes and trial functions provided by the EMC. In particular, we analyze the momentum distribution n(p) with respect to the discontinuity Z as well as the singular behavior at the Fermi surface. We also show that an approximate factorization of the one-body density matrix {rho}(r){approx_equal};{rho}{sub 0}(r){rho}{sub B}(r) holds, with {rho}{sub 0}(r) and {rho}{sub B}(r), respectively, the density matrix of the ideal Fermi gas and the density matrix of a Bose {sup 3}He. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 475288
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 2 Vol. 55; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BOSE-EINSTEIN CONDENSATION
COMPUTERIZED SIMULATION
DENSITY MATRIX
DISTRIBUTION FUNCTIONS
GROUND STATES
HELIUM
LINEAR MOMENTUM
MONTE CARLO METHOD
QUANTUM FLUIDS
WAVE FUNCTIONS