Path Integral Monte Carlo Calculation of the Momentum Distribution of
the Homogeneous Electron Gas at Finite Temperature
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Path Integral Monte Carlo Calculation of the Momentum Distribution of
the Homogeneous Electron Gas at Finite Temperature

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B. Militzer, E. L. Pollock, and D. M. Ceperley

Path integral Monte Carlo (PIMC) simulations are used to calculate the
momentum distribution of the homogeneous electron gas at finite
temperature. This is done by calculating the off-diagonal elements of
the real-space density matrix, represented in PIMC by open paths. It
is demonstrated how the restricted path integral Monte Carlo methods
can be extended in order to deal with open paths in fermionic systems
where a sign problem is present. The computed momentum distribution
shows significant deviations for strong correlation from free fermion
results but agrees with predictions from variational methods.

Submitted to *Phys. Rev. B*, October 16, 2003.