Impedance measurement technique for quantum systems

S. N. Shevchenko

doi:10.1140/epjb/e2008-00061-9

EPJ

Impedance measurement technique for quantum systems

S. N. Shevchenko^a

B. Verkin Institute for Low Temperature Physics and Engineering, 47 Lenin Ave., Kharkov, 61103, Ukraine

Received: 22 March 2007
Revised: 9 July 2007
Published online: 16 February 2008

Abstract

The impedance measurement technique consists in that the phase-dependent (parametric) inductance of the system is probed by the classical tank circuit via measuring the voltage. The notion of the parametric inductance for the impedance measurement technique is revisited for the case when a quantum system is probed. Measurement of the quantum state of the system of superconducting circuits (qubits) is studied theoretically. It is shown that the result of the measurement is defined by the partial energy levels population in the qubits and by its derivative.

PACS: 85.25.Am – Superconducting device characterization, design, and modeling / 85.25.Cp – Josephson devices