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