Short-time decoherence of Josephson charge qubits

Short-time decoherence of Josephson charge qubits in Ohmic and 1/f noise environment

In this paper we investigate the short-time decoherence from Ohmic and 1/f noise of single Josephson charge qubit (JCQ). At first, we use the short-time approximation to obtain the dynamics of the open JCQ. Then we calculate the decoherence the measure of which is chosen as the maximum norm of the deviation density operator. It is shown that the decoherence from 1/f noise plays the central role...

Decoherence in Josephson qubits

A high degree of quantum coherence is a crucial requirement for the implementation of quantum logic devices. Solid state nanodevices seem particularly promising from the point of view of integrability and flexibility in the design. However decoherence is a serious limitation, due to the presence of many types low energy excitations in the “internal” environment and of “external” sources due to ...

Low temperature decoherence and relaxation in charge Josephson junction qubits

Decoherence in Josephson qubits from dielectric loss.

Dielectric loss from two-level states is shown to be a dominant decoherence source in superconducting quantum bits. Depending on the qubit design, dielectric loss from insulating materials or the tunnel junction can lead to short coherence times. We show that a variety of microwave and qubit measurements are well modeled by loss from resonant absorption of two-level defects. Our results demonst...

Short-time decoherence of Josephson charge qubit nonlinearly coupling with its environment

At first, we generally investigate the short-time decoherence of a qubit nonlinearly coupling with a bath. The measure of the decoherence is chosen as the maximum norm of the deviation density operator. Then we concretely investigate the Josephson charge qubit (JCQ) model. It is shown that at the temperature T ∼ 30mK, the loss of fidelity (due to decoherence) of the JCQ is bigger than the DiVin...