Quantum rifling: protecting a qubit from measurement back-action

Abstract

Quantum mechanics postulates that measuring the qubit's wave function results in its collapse, with the recorded discrete outcome designating the particular eigenstate that the qubit collapsed into. We show that this picture breaks down when the qubit is strongly driven during measurement. More specifically, for a fast evolving qubit the measurement returns the time-averaged expectation value of the measurement operator, erasing information about the initial state of the qubit, while completely suppressing the measurement back-action. We call this regime `quantum rifling', as the fast spinning of the Bloch vector protects it from deflection into either of its eigenstates. We study this phenomenon with two superconducting qubits coupled to the same probe field and demonstrate that quantum rifling allows us to measure either one of the qubits on demand while protecting the state of the other from measurement back-action. Our results allow for the implementation of selective read out multiplexing of several qubits, contributing to the efficient scaling up of quantum processors for future quantum technologies.

References in corpus (29)

• Charge insensitive qubit design derived from the Cooper pair box
• Cavity quantum electrodynamics for superconducting electrical circuits: an architecture for quantum computation
• QuTiP 2: A Python framework for the dynamics of open quantum systems
• QuTiP: An open-source Python framework for the dynamics of open quantum systems
• Dynamical decoupling and noise spectroscopy with a superconducting flux qubit
• Decoherence in a superconducting quantum bit circuit
• Observation of quantum jumps in a superconducting artificial atom
• Experimental violation of a Bell's inequality in time with weak measurement
• To catch and reverse a quantum jump mid-flight
• Quantum trajectory approach to circuit QED: Quantum jumps and the Zeno effect
• Quantum back-action of variable-strength measurement
• Rapid high-fidelity multiplexed readout of superconducting qubits
• Continuous weak measurement of quantum coherent oscillations
• Continuous and Pulsed Quantum Zeno Effect
• Mechanically Detecting and Avoiding the Quantum Fluctuations of a Microwave Field
• Rotating-frame relaxation as a noise spectrum analyzer of a superconducting qubit undergoing driven evolution
• Motional Averaging in a Superconducting Qubit
• Gated conditional displacement readout of superconducting qubits
• Dynamics of a mesoscopic qubit under continuous quantum measurement
• Relaxation and Zeno effect in qubit measurements
• Leggett-Garg inequality with a kicked quantum pump
• A Dressed Spin Qubit in Silicon
• Output spectrum of a detector measuring quantum oscillations
• Protecting a solid-state spin from decoherence using dressed spin states
• Qubit feedback and control with kicked quantum nondemolition measurements: A quantum Bayesian analysis
• Dynamics of a qubit while simultaneously monitoring its relaxation and dephasing
• Continuous quantum measurement with independent detector cross-correlations
• Quantum Zeno effect in the strong measurement regime of circuit quantum electrodynamics
• Continuous quantum measurement: inelastic tunnelling suppresses current oscillations

Cited by in corpus (11)

• Demonstration of universal control between non-interacting qubits using the Quantum Zeno effect
• Mirror, mirror: Landau-Zener-Stuckelberg-Majorana interferometry of a superconducting qubit in front of a mirror
• Quantum Zeno effects across a parity-time symmetry breaking transition in atomic momentum space
• Effect of Measurement Backaction on Quantum Clock Precision Studied with a Superconducting Circuit
• Robust Quantum Gates against Correlated Noise in Integrated Quantum Chips
• Retrieval of photon blockade effect in the dispersive Jaynes-Cummings model
• A Multi-Qubit Quantum Gate Using the Zeno Effect
• Driving-induced resonance narrowing in a strongly coupled cavity-qubit system
• Probabilistic motional averaging
• Characterising Polariton States in Non-Dispersive Regime of Circuit Quantum Electrodynamics
• Logical operations with a dynamical qubit in Floquet-Bacon-Shor code