Engineering the quantum measurement process for the persistent current qubit
نویسندگان
چکیده
The SQUID used to measure the flux state of a superconducting flux-based qubit interacts with the qubit and transmits its environmental noise to the qubit, thus causing the relaxation and dephasing of the qubit state. The SQUID–qubit system is analyzed and the effect of the transmittal of environmental noise is calculated. The method presented can also be applied to other quantum systems. 2001 Elsevier Science B.V. All rights reserved. PACS: 03.67.Lx; 74.90.þn; 85.25.Dq; 85.25.Cp J
منابع مشابه
Engineering decoherence in Josephson persistent-current qubits Measurement apparatus and other electromagnetic environments
We discuss the relaxation and dephasing rates that result from the control and the measurement setup itself in experiments on Josephson persistent-current qubits. For control and measurement of the qubit state, the qubit is inductively coupled to electromagnetic circuitry. We show how this system can be mapped on the spin-boson model, and how the spectral density of the bosonic bath can be deri...
متن کاملMeasurement and on-chip control of a niobium persistent current qubit
The persistent current qubit is a superconducting ring interrupted by three Josephson junctions. Its two quantum states have circulating currents in opposite directions which can be measured by a dc SQUID magnetometer. This work examines a persistent current qubit fabricated in niobium, using Lincoln Laboratory's DPARTS process. Measurements of the niobium qubit show a promisingly high subgap r...
متن کاملBistability in the Electric Current through a Quantum-Dot Capacitively Coupled to a Charge-Qubit
We investigate the electronic transport through a single-level quantum-dot which is capacitively coupled to a charge-qubit. By employing the method of nonequilibrium Green's functions, we calculate the electric current through quantum dot at finite bias voltages. The Green's functions and self-energies of the system are calculated perturbatively and self-consistently to the second order of inte...
متن کاملFabrication and measurement of a niobium persistent current qubit
Recent successes with superconducting Josephson junction qubits make them prime candidates for the implementation of quantum computing. This doctoral thesis details the study of a niobium Josephson junction circuit for quantum computing applications. The thesis covers two main areas: 1) the fabrication of sub-micron niobium Josephson junction devices using a Nb/Al/AlO./Nb trilayer process and 2...
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 کامل