Lattice calculation of thermal properties of low-density neutron matter with pionless NN effective field theory

Journal Article · Fri May 15 00:00:00 EDT 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.79.054002· OSTI ID:21289887

Abe, T ^[1]; Seki, R ^[2]

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1. Department of Physics, Tokyo Institute of Technology, Megro, Tokyo 152-8551 (Japan)
2. Department of Physics and Astronomy, California State University, Northridge, Northridge, California 91330 (United States)

Thermal properties of low-density neutron matter are investigated by determinantal quantum Monte Carlo lattice calculations on 3+1 dimensional cubic lattices. Nuclear effective field theory (EFT) is applied using the pionless single- and two-parameter neutron-neutron interactions, determined from the {sup 1}S{sub 0} scattering length and effective range. The determination of the interactions and the calculations of neutron matter are carried out consistently by applying EFT power counting rules. The thermodynamic limit is taken by the method of finite-size scaling, and the continuum limit is examined in the vanishing lattice filling limit. The {sup 1}S{sub 0} pairing gap at T{approx_equal}0 is computed directly from the off-diagonal long-range order of the spin pair-pair correlation function and is found to be approximately 30% smaller than BCS calculations with the conventional nucleon-nucleon potentials. The critical temperature T{sub c} of the normal-to-superfluid phase transition and the pairing temperature scale T* are determined, and the temperature-density phase diagram is constructed. The physics of low-density neutron matter is clearly identified as being a BCS-Bose-Einstein condensation crossover.

• OSTI ID: 21289887
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 79, Issue 5; Other Information: DOI: 10.1103/PhysRevC.79.054002; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BCS THEORY
BOSE-EINSTEIN CONDENSATION
COMPUTERIZED SIMULATION
CORRELATION FUNCTIONS
CRITICAL TEMPERATURE
CUBIC LATTICES
DENSITY
LATTICE FIELD THEORY
MONTE CARLO METHOD
NEUTRON DENSITY
NEUTRON-NEUTRON INTERACTIONS
NUCLEAR MATTER
NUCLEON-NUCLEON POTENTIAL
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
SCALING
SCATTERING LENGTHS
SPIN
SUPERFLUIDITY
THREE-DIMENSIONAL CALCULATIONS