thstate.m

来自「该算法是用于量子运算的matlab程序」· M 代码 · 共 24 行

% thstate   Thermal state of a system with a given Hamiltonian
%    thstate(H,kT) is the thermal state of a system described by a
%    Hamiltonian at temperature kT. 

% Copyright (C) 2005  Geza Toth    E.mail: [e-mail]
%
% This program is free software; you can redistribute it and/or
% modify it under the terms of the GNU General Public License
% as published by the Free Software Foundation; see gpl.txt
% of this subroutine package.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
% 
% You should have received a copy of the GNU General Public License
% along with this program; if not, write to the Free Software
% Foundation, Inc., 51 Franklin Street, Fifth Floor, 
% Boston, MA  02110-1301, USA.

function rho=thstate(H,kT)
   rho=expm(-H/kT);
   rho=rho/trace(rho);