MARC보기
LDR00000nam u2200205 4500
001000000432646
00520200224133247
008200131s2019 ||||||||||||||||| ||eng d
020 ▼a 9781687915337
035 ▼a (MiAaPQ)AAI13895999
040 ▼a MiAaPQ ▼c MiAaPQ ▼d 247004
0820 ▼a 530
1001 ▼a Warrington, Neill C.
24510 ▼a Taming the Sign Problem in Lattice Field Theory with Deformed Path Integral Contours.
260 ▼a [S.l.]: ▼b University of Maryland, College Park., ▼c 2019.
260 1 ▼a Ann Arbor: ▼b ProQuest Dissertations & Theses, ▼c 2019.
300 ▼a 129 p.
500 ▼a Source: Dissertations Abstracts International, Volume: 81-05, Section: B.
500 ▼a Advisor: Bedaque, Paulo.
5021 ▼a Thesis (Ph.D.)--University of Maryland, College Park, 2019.
506 ▼a This item must not be sold to any third party vendors.
520 ▼a In this thesis a generic method for taming the sign problem is developed. The sign problem is the name given to the difficult task of numerically integrating a highly oscillatory integral, and the sign problem inhibits our ability to understand the properties of a wide range of systems of interest in theoretical physics. Particularly notably for nuclear physics, the sign problem prevents the calculation of the properties of QCD at finite baryon density, thereby precluding an understanding of the dense nuclear matter found in the center of a neutron star. The central idea developed in this thesis is to use the multidimensional generalization of Cauchy's Integral Theorem to deform the Feynman Path Integral of lattice fields theories into complexified field space to manifolds upon which the phase oscillations which cause the sign problem are gentle. Doing so allows calculations of theories with sign problems. Two practical manifold deformation methods, the holomorphic gradient flow and the sign-optimized manifold method, are developed. The holomorphic gradient flow, a generalization of the Lefschetz thimble method, continuously deforms the original path integration domain to a complex manifold via an evolution dictated by a complex first order differential equation. The sign-optimized manifold method is a way to generate a manifold with gentle phase oscillations by minimizing the sign problem in a parameterized family of manifolds through stochastic gradient ascent. With an eye toward QCD at finite density, the Cauchy's Theorem approach is applied to relativistic quantum field theories of fermions at finite density throughout this thesis. Finally, these methods are general and can be applied to both bosonic and fermionic theories, as well as Minkowski path integrals describing real-time dynamics.
590 ▼a School code: 0117.
650 4 ▼a Physics.
650 4 ▼a Nuclear physics.
650 4 ▼a Astrophysics.
650 4 ▼a High temperature physics.
650 4 ▼a Quantum physics.
690 ▼a 0605
690 ▼a 0599
690 ▼a 0596
690 ▼a 0597
690 ▼a 0756
71020 ▼a University of Maryland, College Park. ▼b Physics.
7730 ▼t Dissertations Abstracts International ▼g 81-05B.
773 ▼t Dissertation Abstract International
790 ▼a 0117
791 ▼a Ph.D.
792 ▼a 2019
793 ▼a English
85640 ▼u http://www.riss.kr/pdu/ddodLink.do?id=T15491664 ▼n KERIS ▼z 이 자료의 원문은 한국교육학술정보원에서 제공합니다.
980 ▼a 202002 ▼f 2020
990 ▼a ***1008102
991 ▼a E-BOOK