Selective quantum evolution of a qubit state due to continuous measurement
نویسنده
چکیده
We consider a two-level quantum system ~qubit! that is continuously measured by a detector. The information provided by the detector is taken into account to describe the evolution during a particular realization of the measurement process. We discuss the Bayesian formalism for such ‘‘selective’’ evolution of an individual qubit and apply it to several solid-state setups. In particular, we show how to suppress qubit decoherence using continuous measurement and a feedback loop.
منابع مشابه
Noisy quantum measurement of solid-state qubits: Bayesian approach
We discuss a recently developed formalism which describes the quantum evolution of a solid-state qubit due to its continuous measurement. In contrast to the conventional ensembleaveraged formalism, it takes into account the measurement record and therefore is able to consider individual realizations of the measurement process. The formalism provides testable experimental predictions and can be ...
متن کاملQuantum Bayesian approach to circuit QED measurement with moderate bandwidth
We consider continuous quantum measurement of a superconducting qubit in the circuit QED setup with a moderate bandwidth of the measurement resonator, i.e., when the “bad-cavity” limit is not applicable. The goal is a simple description of the quantum evolution due to measurement, i.e., the measurement backaction. Extending the quantum Bayesian approach previously developed for the bad-cavity r...
متن کاملDecoherence effects on quantum Fisher information of multi-qubit W states
Quantum fisher information of a parameter characterizing the sensitivity of a state with respect to parameter changes. In this paper, we study the quantum fisher information of the W state for four, five, six and seven particles in decoherence channels, such as amplitude damping, phase damping and depolarizing channel. Using Krauss operators for decoherence channels components, we investigate t...
متن کاملContinuous measurement of entangled qubits
The problem of quantum measurement of a qubit ~twolevel system! received renewed attention recently in relation to its importance for quantum computing. The case of sufficiently fast ~instantaneous! measurement can be readily described by ‘‘orthodox’’ collapse postulate @1#, and this is the case assumed at present by all quantum algorithms. However, in practice, especially for solid-state qubit...
متن کاملNoisy quantum measurement of solid-state qubits
The quantum evolution of an individual solid-state qubit during the process of its continuous measurement can be described by the recently developed Bayesian formalism. In contrast to the conventional ensemble-averaged formalism, it takes into account the measurement record (in a way similar to the standard Bayesian analysis) and therefore is able to consider individual realizations of the meas...
متن کامل