Pulse-qubit interaction in a superconducting circuit under frictively dissipative environment

TL;DR

This paper investigates how environmental dissipation affects microwave pulse shapes during qubit control in superconducting circuits, revealing asymmetric multi-hump pulses and transitions to solitonic or pulse train regimes.

Contribution

It provides a theoretical analysis of pulse deformation caused by dissipation, highlighting the environmental impact on pulse shape and qubit interaction in superconducting circuits.

Findings

Pulse shape becomes asymmetric with multi-humps due to dissipation.

At zero dissipation, pulses are solitonic; at high dissipation, they form pulse trains.

Environmental effects influence both envelope and phase of the propagating pulse.

Abstract

Microwave pulses are used ubiquitously to control and measure qubits fabricated on superconducting circuits. Due to continual environmental coupling, the qubits undergo decoherence both when it is free and during its interaction with the microwave pulse. As quantum logic gates are executed through pulse-qubit interaction, we study theoretically the decoherence-induced effects during the interaction, especially the variations of the pulse, under a dissipative environment with linear spectral distribution. We find that a transmissible pulse of finite width adopts an asymmetric multi-hump shape, due to the imbalanced pumping and emitting rates of the qubit during inversion when the environment is present. The pulse shape reduces to a solitonic pulse at vanishing dissipation and a pulse train at strong dissipation. We give detailed analysis of the environmental origin from both the perspectives of envelope and phase of the propagating pulse.