Indirect control of quantum system via accessor: pure coherent control without system excitation

Indirect controllability of degenerate quantum systems with quantum accessor

Complete controllability of degenerate quantum system using quantum accessor modeled as a qubit chain with nearest neighborhood coupling is investigated. Sufficient conditions on the length of accessor and the way of coupling between controlled system and accessor are obtained. General approach to arbitrary finite system is presented and two and three level degenerate systems are investigated in detail.

Indirect control with quantum accessor: coherent control by initial state preparation

This is the second one in our series of papers on indirect quantum control assisted by quantum accessor. In this paper we propose and study a new class of indirect quantum control(IDQC) scheme based on the initial states preparation of the accessor. In the present scheme, after the initial state of the accessor is properly prepared, the system is controlled by repeatedly switching on and off the interaction between the system and the accessor. This is different from the protocol of our first paper, where we manipulate the interaction between the controlled system and the accessor. We prove the…

Indirect control with quantum accessor (I): coherent control of multi-level system via qubit chain

Indirect controllability of an arbitrary finite dimensional quantum system (N-dimensional qudit) through a quantum accessor is investigated. Here, The qudit is coupled to a quantum accessor which is modeled as a fully controllable spin chain with nearest neighbor (anisotropic) XY-coupling. The complete controllability of such indirect control system is investigated in detail. The general approach is applied to the indirect controllability of two and three dimensional quantum systems. For two and three dimensional systems, a simpler indirect control scheme is also presented.

由于环境诱导的间接相互作用增强非马尔可夫性

Enhancement of non-Markovianity due to environment-induced indirect interaction

本文研究了由环境诱导的间接相互作用如何增强两能级系统的非马尔可夫性，揭示了多量子比特系统中退相干控制的潜在方法。

Indirect control of the asymptotic states of a quantum dynamical semigroup

In the dynamics of open quantum systems, the interaction with the external environment usually leads to a contraction of the set of reachable states for the system as time increases, eventually shrinking to a single stationary point. In this contribution we describe to what extent it is possible to modify this asymptotic state by means of indirect control, that is by using an auxiliary system coupled to the target system in order to affect its dynamics, when there is a purely dissipative coupling between the two systems. We prove that, also in this restrictive case, it is possible to modify th…

Probabilistic Quantum Control Via Indirect Measurement

The most basic scenario of quantum control involves the organized manipulation of pure dynamical states of the system by means of unitary transformations. Recently, Vilela Mendes and Mank'o have shown that the conditions for controllability on the state space become less restrictive if unitary control operations may be supplemented by projective measurement. The present work builds on this idea, introducing the additional element of indirect measurement to achieve a kind of remote control. The target system that is to be remotely controlled is first entangled with another identical system, cal…