Difference between revisions of "Much more about QMC here"

From Qmcchem
Jump to navigation Jump to search
 
(One intermediate revision by the same user not shown)
Line 1: Line 1:
 
Quantum Monte Carlo methods are powerful probabilistic approaches for computing quantum averages of a N-body quantum system described by a Schrödinger equation. Many QMC variants known under various acronyms exist in the literature. We propose here to classify them as follows:
 
Quantum Monte Carlo methods are powerful probabilistic approaches for computing quantum averages of a N-body quantum system described by a Schrödinger equation. Many QMC variants known under various acronyms exist in the literature. We propose here to classify them as follows:
<ul>
+
 
<li> Zero-temperature (T=O) and Finite-temperature (T diff 0) QMC methods
+
* Zero-temperature (T=O) and Finite-temperature (T diff 0) QMC methods
<li> QMC defined in continuous or discrete (lattice) configuration space
+
* QMC defined in continuous or discrete (lattice) configuration space
<li>  QMC for Boltzmanon, Fermion, or Boson particles.
+
* QMC for Boltzmanon, Fermion, or Boson particles.
</ul>
 
  
 
In what follows a self-contained presentation of QMC is proposed. We shall concentrate on the T=0 QMC approaches defined in a continuous space corresponding to electronic structure theory conditions.
 
In what follows a self-contained presentation of QMC is proposed. We shall concentrate on the T=0 QMC approaches defined in a continuous space corresponding to electronic structure theory conditions.
  
In order to make easier the presentation, we shall first consider the case of a one-dimensional system defined in a continuous space and no particular statistics. Second, we shall say a few words about the generalization to arbitrary number of dimensions d (actually, d=3N where N is the number of electrons). It is a nice aspect of the vast majority of Monte Carlo methods that such a generalization is in general trivial. Finally, we shall consider how to introduce into QMC the specific constraints due to the Pauli principle.  
+
In order to make easier the presentation, we shall first consider the case of a one-dimensional system defined in a continuous space and no particular statistics. Second, we shall say a few words about the generalization to arbitrary number d of dimensions (actually, d=3N where N is the number of electrons). Remark that it is a nice aspect of the vast majority of Monte Carlo methods that such a generalization does not bring additional difficulties. Finally, we shall consider how to introduce into QMC the specific constraints due to the Pauli principle.  
  
 
I. T=0 QMC for a continuous one-dimensional system with no specific symmetry constraints
 
I. T=0 QMC for a continuous one-dimensional system with no specific symmetry constraints

Latest revision as of 16:42, 25 October 2010

Quantum Monte Carlo methods are powerful probabilistic approaches for computing quantum averages of a N-body quantum system described by a Schrödinger equation. Many QMC variants known under various acronyms exist in the literature. We propose here to classify them as follows:

  • Zero-temperature (T=O) and Finite-temperature (T diff 0) QMC methods
  • QMC defined in continuous or discrete (lattice) configuration space
  • QMC for Boltzmanon, Fermion, or Boson particles.

In what follows a self-contained presentation of QMC is proposed. We shall concentrate on the T=0 QMC approaches defined in a continuous space corresponding to electronic structure theory conditions.

In order to make easier the presentation, we shall first consider the case of a one-dimensional system defined in a continuous space and no particular statistics. Second, we shall say a few words about the generalization to arbitrary number d of dimensions (actually, d=3N where N is the number of electrons). Remark that it is a nice aspect of the vast majority of Monte Carlo methods that such a generalization does not bring additional difficulties. Finally, we shall consider how to introduce into QMC the specific constraints due to the Pauli principle.

I. T=0 QMC for a continuous one-dimensional system with no specific symmetry constraints