STOCHASTIC DILATION OF A QUANTUM DYNAMICAL SEMIGROUP ON A SEPARABLE UNITAL C* ALGEBRA

2000 ◽  
Vol 03 (01) ◽  
pp. 177-184 ◽  
Author(s):  
DEBASHISH GOSWAMI ◽  
ARUP KUMAR PAL ◽  
KALYAN B. SINHA
Keyword(s):  
Von Neumann Algebra ◽  
Quantum Dynamical Semigroup ◽  
Von Neumann ◽  
C Algebra ◽  
Quantum Dynamical ◽  
Dynamical Semigroup ◽  
Algebraic Framework ◽  
Uniformly Continuous

Given a uniformly continuous quantum dynamical semigroup on a separable unital C* algebra, we construct a canonical Evans–Hudson (E-H) dilation. Such a result was already proved by Goswami and Sinha6 in the von Neumann algebra setup, which has been extended to the C* algebraic framework in this paper. The authors make use of the coordinate-free calculus and results of Ref. 6, but the proof of the existence of structure maps differs from that of Ref. 6.

scholarly journals A REMARK ON THE STRUCTURE OF SYMMETRIC QUANTUM DYNAMICAL SEMIGROUPS ON VON NEUMANN ALGEBRAS

2002 ◽  
Vol 05 (04) ◽  
pp. 571-579 ◽  
Author(s):  
SERGIO ALBEVERIO ◽  
DEBASHISH GOSWAMI
Keyword(s):  
Von Neumann Algebra ◽  
Von Neumann Algebras ◽  
Type I ◽  
Quantum Dynamical Semigroup ◽  
Von Neumann ◽  
Matrix Algebras ◽  
Quantum Dynamical ◽  
Dynamical Semigroup ◽  
Quantum Dynamical Semigroups ◽  
Symmetric Quantum

We study the structure of the generator of a symmetric, conservative quantum dynamical semigroup with norm-bounded generator on a von Neumann algebra equipped with a faithful semifinite trace. For von Neumann algebras with Abelian commutant (i.e. type I von Neumann algebras), we give a necessary and sufficient algebraic condition for the generator of such a semigroup to be written as a sum of square of self-adjoint derivations of the von Neumann algebra. This generalizes some of the results obtained by Albeverio, Høegh-Krohn and Olsen1 for the special case of the finite-dimensional matrix algebras. We also study similar questions for a class of quantum dynamical semigroups with unbounded generators.

scholarly journals Structure of block quantum dynamical semigroups and their product systems

2020 ◽  
Vol 23 (01) ◽  
pp. 2050001
Author(s):  
B. V. Rajarama Bhat ◽  
U. Vijaya Kumar
Keyword(s):  
Von Neumann Algebra ◽  
Markov Semigroup ◽  
Map Building ◽  
Quantum Dynamical Semigroup ◽  
Von Neumann ◽  
Quantum Dynamical ◽  
Product Systems ◽  
Dynamical Semigroup ◽  
Quantum Markov Semigroup ◽  
Unit Formula

Paschke’s version of Stinespring’s theorem associates a Hilbert [Formula: see text]-module along with a generating vector to every completely positive map. Building on this, to every quantum dynamical semigroup (QDS) on a [Formula: see text]-algebra [Formula: see text] one may associate an inclusion system [Formula: see text] of Hilbert [Formula: see text]-[Formula: see text]-modules with a generating unit [Formula: see text]. Suppose [Formula: see text] is a von Neumann algebra, consider [Formula: see text], the von Neumann algebra of [Formula: see text] matrices with entries from [Formula: see text]. Suppose [Formula: see text] with [Formula: see text] is a QDS on [Formula: see text] which acts block-wise and let [Formula: see text] be the inclusion system associated to the diagonal QDS [Formula: see text] with the generating unit [Formula: see text] It is shown that there is a contractive (bilinear) morphism [Formula: see text] from [Formula: see text] to [Formula: see text] such that [Formula: see text] for all [Formula: see text] We also prove that any contractive morphism between inclusion systems of von Neumann [Formula: see text]-[Formula: see text]-modules can be lifted as a morphism between the product systems generated by them. We observe that the [Formula: see text]-dilation of a block quantum Markov semigroup (QMS) on a unital [Formula: see text]-algebra is again a semigroup of block maps.

MINIMAL QUANTUM DYNAMICAL SEMIGROUP ON A VON NEUMANN ALGEBRA

1999 ◽  
Vol 02 (02) ◽  
pp. 221-239 ◽  
Author(s):  
DEBASHISH GOSWAMI ◽  
KALYAN B. SINHA
Keyword(s):  
State Space ◽  
Von Neumann Algebra ◽  
Sufficient Conditions ◽  
Markov Semigroup ◽  
Quantum Dynamical Semigroup ◽  
Von Neumann ◽  
Arbitrary State ◽  
Quantum Dynamical ◽  
Dynamical Semigroup ◽  
Necessary And Sufficient

Given a formal unbounded generator, the minimal quantum dynamical semigroup on a von Neumann algebra is constructed. A set of equivalent necessary and sufficient conditions for the conservativity of the minimal semigroup is given and in the case when it is not conservative, a distinguished family of conservative perturbations of the semigroup is studied. Finally, some of these results are applied to the classical Markov semigroup with arbitrary state space.

APPROXIMATELY INNER FLOWS ON SEPARABLE C*-ALGEBRAS

2002 ◽  
Vol 14 (07n08) ◽  
pp. 649-673 ◽  
Author(s):  
AKITAKA KISHIMOTO
Keyword(s):  
Irreducible Representation ◽  
Von Neumann Algebra ◽  
Automorphism Groups ◽  
Unitary Groups ◽  
Type I ◽  
Von Neumann ◽  
C Algebra ◽  
C Algebras ◽  
Inner Automorphism ◽  
Uniformly Continuous

We present two types of result for approximately inner one-parameter automorphism groups (referred to as AI flows hereafter) of separable C*-algebras. First, if there is an irreducible representation π of a separable C*-algebra A such that π(A) does not contain non-zero compact operators, then there is an AI flow α such that π is α-covariant and α is far from uniformly continuous in the sense that α induces a flow on π(A) which has full Connes spectrum. Second, if α is an AI flow on a separable C*-algebra A and π is an α-covariant irreducible representation, then we can choose a sequence (hn) of self-adjoint elements in A such that αt is the limit of inner flows Ad eithn and the sequence π(eithn) of one-parameter unitary groups (referred to as unitary flows hereafter) converges to a unitary flow which implements α in π. This latter result will be extended to cover the case of weakly inner type I representations. In passing we shall also show that if two representations of a separable simple C*-algebra on a separable Hilbert space generate the same von Neumann algebra of type I, then there is an approximately inner automorphism which sends one into the other up to equivalence.

scholarly journals REMARKS ON THE STRUCTURE OF DIRICHLET FORMS ON STANDARD FORMS OF VON NEUMANN ALGEBRAS

2005 ◽  
Vol 08 (02) ◽  
pp. 179-197 ◽  
Author(s):  
YONG MOON PARK
Keyword(s):  
Von Neumann Algebra ◽  
Von Neumann Algebras ◽  
Bounded Operator ◽  
Standard Form ◽  
Adjoint Operator ◽  
Sufficient Conditions ◽  
Dirichlet Forms ◽  
Quantum Dynamical Semigroup ◽  
Von Neumann ◽  
Dynamical Semigroup

For a von Neumann algebra ࡕ acting on a Hilbert space ℋ with a cyclic and separating vector ξ0, we investigate the structure of Dirichlet forms on the natural standard form associated with the pair (ࡕ, ξ0). For a general bounded Lindblad type generator L of a conservative quantum dynamical semigroup on ࡕ, we give sufficient conditions so that the bounded operator H induced by L via the symmetric embedding of ࡕ into ℋ to be self-adjoint. It turns out that the self-adjoint operator H can be written in the form of a Dirichlet operator associated to a Dirichlet form given in Ref. 23. In order to make the connection possible, we also extend the range of applications of the formula in Ref. 23.

NONLINEAR MARKOV SEMIGROUPS ON C*-ALGEBRAS

2013 ◽  
Vol 16 (01) ◽  
pp. 1350004 ◽  
Author(s):  
P. ŁUGIEWICZ ◽  
R. OLKIEWICZ ◽  
B. ZEGARLINSKI
Keyword(s):  
Sufficient Conditions ◽  
Markov Semigroup ◽  
Markov Semigroups ◽  
Quantum Dynamical Semigroup ◽  
C Algebra ◽  
C Algebras ◽  
Quantum Dynamical ◽  
Dynamical Semigroup ◽  
Nonlinear Quantum ◽  
Duality Map

A notion of a nonlinear quantum dynamical semigroup is introduced and discussed. Some sufficient conditions, expressed solely in terms of the duality map, in order that a multivalued mapping on a C*-algebra generates the nonlinear Markov semigroup are proposed.

scholarly journals Nonlinear extension of the quantum dynamical semigroup

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 420
Author(s):  
Jakub Rembieliński ◽  
Paweł Caban
Keyword(s):  
Type Equation ◽  
Solar Neutrinos ◽  
Spin Density Matrix ◽  
Equivalence Of Ensembles ◽  
Quantum Dynamical Semigroup ◽  
Semigroup Property ◽  
Quantum Dynamical ◽  
Dynamical Semigroup ◽  
Generated Family ◽  
Linearity Condition

In this paper we consider deterministic nonlinear time evolutions satisfying so called convex quasi-linearity condition. Such evolutions preserve the equivalence of ensembles and therefore are free from problems with signaling. We show that if family of linear non-trace-preserving maps satisfies the semigroup property then the generated family of convex quasi-linear operations also possesses the semigroup property. Next we generalize the Gorini-Kossakowski-Sudarshan-Lindblad type equation for the considered evolution. As examples we discuss the general qubit evolution in our model as well as an extension of the Jaynes-Cummings model. We apply our formalism to spin density matrix of a charged particle moving in the electromagnetic field as well as to flavor evolution of solar neutrinos.

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