Dynamics of a qubit-oscillator system with periodically varying coupling

Dissipative Dynamics of a Qubit Coupled to a Nonlinear Oscillator

We consider the dissipative dynamics of a qubit coupled to a nonlinear oscillator (NO) embedded in an Ohmic environment. By treating the nonlinearity up to first order and applying Van Vleck perturbation theory up to second order in the qubit-NO coupling, we derive an analytical expression for the eigenstates and eigenfunctions of the coupled qubit-NO system beyond the rotating wave approximati...

Observation of the Bloch-Siegert shift in a qubit-oscillator system in the ultrastrong coupling regime.

We measure the dispersive energy-level shift of an LC resonator magnetically coupled to a superconducting qubit, which clearly shows that our system operates in the ultrastrong coupling regime. The large mutual kinetic inductance provides a coupling energy of ≈ 0.82 GHz, requiring the addition of counter-rotating-wave terms in the description of the Jaynes-Cummings model. We find a 50 MHz Bloch...

Dynamics of the pendulum with periodically varying length

Super operator Technique in Investigation of the Dynamics of a Two Non-Interacting Qubit System Coupled to a Thermal Reservoir

In this paper, we clarify the applicability of the super operator technique for describing the dissipative quantum dynamics of a system consists of two qubits coupled with a thermal bath at finite temperature. By using super operator technique, we solve the master equation and find the matrix elements of the density operator. Considering the qubits to be initially prepared in a general mixed st...

Universal control of an oscillator with dispersive coupling to a qubit

Stefan Krastanov,1 Victor V. Albert,1 Chao Shen,1 Chang-Ling Zou,1,2 Reinier W. Heeres,1 Brian Vlastakis,1 Robert J. Schoelkopf,1 and Liang Jiang1 1Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA 2Key Lab of Quantum Information, University of Science and Technology of China, Hefei 230026, Anhui, China (Received 27 February 2015; published 21 Octobe...