The tunable 0-\texorpdfstring{$\pi$}{Lg} qubit: Dynamics and Relaxation

Abstract

We present a systematic treatment of a 0-\texorpdfstring{$\pi$}{Lg} qubit in the presence of a time-dependent external flux. A gauge-invariant Lagrangian and the corresponding Hamiltonian is obtained. The effect of the flux noise on the qubit relaxation is obtained using perturbation theory. Under a time-dependent drive of sinusoidal form, the survival probability, and transition probabilities have been studied for different strengths and frequencies. The driven qubit is shown to possess coherent oscillations among two distinct states for a weak to moderate strength close to resonant frequencies of the unperturbed qubit. The parameters can be chosen to prepare the system in its ground state. This feature paves the way to prolong the lifetime by combining ideas from weak measurement and quantum Zeno effect. We believe that this is an important variation of a topologically protected qubit which is tunable.

References in corpus (15)

• Quantum Computing in the NISQ era and beyond
• To catch and reverse a quantum jump mid-flight
• Introduction to Quantum Electromagnetic Circuits
• Protected gates for superconducting qubits
• Superconducting Nanocircuits for Topologically Protected Qubits
• Experimental realization of an intrinsically error-protected superconducting qubit
• Superconducting circuit protected by two-Cooper-pair tunneling
• Circuit quantization in the presence of time-dependent external flux
• Coherence properties of the 0-$\pi$ qubit
• Protected Josephson Rhombi Chains
• Bifluxon: Fluxon-Parity-Protected Superconducting Qubit
• Understanding degenerate ground states of a protected quantum circuit in the presence of disorder
• Protected qubit based on a superconducting current mirror
• Engineering two-qubit mixed states with weak measurements
• Protection of qubits by nonlinear resonances