# Keyword Analysis & Research: density matrix quantum mechanics

## Frequently Asked Questions

What is density matrix?

The density matrix is a representation of a linear operator called the density operator. The density matrix is obtained from the density operator by choice of basis in the underlying space. In practice, the terms density matrix and density operator are often used interchangeably.

What is a dense matrix?

The density matrix or density operator is an alternate representation of the state of a quantum system for which we have previously used the wavefunction.

What good is quantum mechanics?

Quantum Mechanics is also essential in attempting to come up with a "Grand Unified Theory" of matter. Such a theory would go a long way towards explaining how and why the universe exists, and how we may gain best advantage from the natural Physics of the universe, e.g. finding new ways of extracting mater from any source of matter, (or even ...

What is the reduced density matrix?

Reduced density operator/matrix A B The composite, total system AB is in the state . The reduced density operator of system A is by definition where the partial trace over B is defined by with any vectors in A (B), and the linearity property of the trace. The reduced density operator describes completely all the ...