Surjective bounded operator on a Hilbert space preserving the inner product
For unitarity in physics, see Unitarity (physics).
In functional analysis, a unitary operator is a surjective bounded operator on a Hilbert space that preserves the inner product. Unitary operators are usually taken as operating on a Hilbert space, but the same notion serves to define the concept of isomorphism between Hilbert spaces.
functional analysis, a unitaryoperator is a surjective bounded operator on a Hilbert space that preserves the inner product. Unitaryoperators are usually taken...
are the same space, a unitary transformation is an automorphism of that Hilbert space, and then it is also called a unitaryoperator. A closely related notion...
mathematics, a unitary representation of a group G is a linear representation π of G on a complex Hilbert space V such that π(g) is a unitaryoperator for every...
decomposition of antiunitary operators contrasts with the spectral decomposition of unitaryoperators. In particular, a unitaryoperator on a complex Hilbert...
Unitary equivalence may refer to: Unitary equivalence of bounded operators in Hilbert space; see self-adjoint operatorUnitary equivalence of a unitary...
mechanics, such as state vectors, probability amplitudes, unitaryoperators, and Hermitian operators, emerge naturally from the classical Maxwell's equations...
unique). The unitaryoperator U is not unique. Rather it is possible to determine a "natural" unitaryoperator as follows: AP+ is a unitaryoperator from the...
limiting argument. Furthermore, F : L2(Rn) → L2(Rn) is a unitaryoperator. For an operator to be unitary it is sufficient to show that it is bijective and preserves...
performed by classical circuits. Quantum gates are unitaryoperators, and are described as unitary matrices relative to some orthonormal basis. Usually...
t units of time on the state of an isolated system S is given by a unitaryoperator Ut on the Hilbert space H associated to S. This means that if the system...
vectors are considered equivalent if they are proportional.] Thus, a unitaryoperator that is a multiple of the identity actually acts as the identity on...
constant-coefficient differential operator is unitarily equivalent to a multiplication operator. Indeed, the unitaryoperator that implements this equivalence...
an eigenstate of the annihilation (lowering) operator. The displacement operator is a unitaryoperator, and therefore obeys D ^ ( α ) D ^ † ( α ) = D...
into the group of unitaryoperators. If G is a compact Lie group, every finite-dimensional representation is equivalent to a unitary one. Each representation...
\qquad z=r\,e^{i\theta }} where the operators inside the exponential are the ladder operators. It is a unitaryoperator and therefore obeys S ( ζ ) S † (...
set Stone's theorem on one-parameter unitary groups Holomorphic functional calculus Spectral theory Compact operator Laplace transform Fredholm theory Liouville–Neumann...
claim. A hyponormal compact operator (in particular, a subnormal operator) is normal. The spectrum of a unitaryoperator U lies on the unit circle in...