Scalable superconducting qubit circuits using dressed states

TL;DR

This paper proposes a method to scale superconducting qubit circuits by using dressed states created through a controllable electromagnetic field, enabling selective coupling and decoupling of qubits for efficient quantum information transfer.

Contribution

It introduces a novel approach utilizing dressed states with TDEF to achieve scalable and controllable coupling in superconducting qubit circuits.

Findings

Dressed states enable selective qubit coupling.

The method allows scalable quantum information transfer.

Controllable TDEF facilitates qubit-bus interactions.

Abstract

We study a coupling/decoupling method between a superconducting qubit and a data bus that uses a controllable time-dependent electromagnetic field (TDEF). As in recent experiments, the data bus can be either an LC circuit or a cavity field. When the qubit and the data bus are initially fabricated, their detuning should be made far larger than their coupling constant, so these can be treated as two independent subsystems. However, if a TDEF is applied to the qubit, then a "dressed qubit" (i.e., qubit plus the electromagnetic field) can be formed. By choosing appropriate parameters for the TDEF, the dressed qubit can be coupled to the data bus and, thus, the qubit and the data bus can exchange information with the assistance of the TDEF. This mechanism allows the scalability of the circuit to many qubits. With the help of the TDEF, any two qubits can be selectively coupled to (and decoupled from) a common data bus. Therefore, quantum information can be transferred from one qubit to another.