Defects and Impurities in Solid $^4$He

ORAL

Abstract

We perform path integral Monte Carlo studies of defects and impurities in solid $^4$He near the low temperature melting transition. The worm algorithm, recently developed for continuum systems, is used to study off-diagonal properties such as the one-body density matrix (OBDM). While this quantity approaches zero exponentially with increasing particle displacement for the ``pure'' solid, interstitial defects and $^3$He impurities appear to enhance and/or stabilize the OBDM at long distances. Thus, imperfections in solid helium may lead to the formation of a condensate. These calculations are repeated for two-dimensional solid helium, and compared with results from lattice boson models.

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Authors

  • Keola Wierschem

    MARTECH, Dept. of Physics, Florida State University

  • Efstratios Manousakis

    MARTECH \& Physics Department, FSU, Tallahassee, FL \& University of Athens, Greece, Department of Physics, Florida State University, USA, and Department of Physics, University of Athens, Greece, MARTECH, Dept. of Physics, Florida State University and University of Athens, Greece, Florida State University, MARTECH and Physics Department, FSU, Tallahassee, FL and University of Athens, Greece, Physics Department, Florida State University, USA, and Physics Department, University of Athens, Greece