Quantum jumps of sound

Abstract

Quantum mechanics predicts that a vibrating object's energy comes in discrete packets, yet no measurement of its position reveals this discreteness. Resolving individual energy levels requires a qualitatively different measurement, one coupling to the resonator's energy rather than its displacement. We use a superconducting qubit dispersively coupled to a nanomechanical resonator to perform repeated quantum nondemolition measurements of the phonon number. An aligned transfer-print technique integrating the qubit and resonator yields a mechanical lifetime of $T_1=2.1$ milliseconds and a dispersive shift of $2\chi /2\pi =328$ kilohertz per phonon. We heralded single-phonon states with 85% fidelity and observed quantum jumps between the resonator's first excited state and ground state. These discontinuous transitions are a striking manifestation of quantum mechanics in a massive, vibrating object.

12 pages, 11 figures

References in corpus (23)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• Charge insensitive qubit design derived from the Cooper pair box
• Quantum jumps of light recording the birth and death of a photon in a cavity
• Progressive field-state collapse and quantum non-demolition photon counting
• Quantum acoustics with superconducting qubits
• Qubit-photon interactions in a cavity: Measurement induced dephasing and number splitting
• Phonon-mediated quantum state transfer and remote qubit entanglement
• Creation and control of multi-phonon Fock states in a bulk acoustic wave resonator
• Building a fault-tolerant quantum computer using concatenated cat codes
• Tracking Photon Jumps with Repeated Quantum Non-Demolition Parity Measurements
• Searching for Dark Matter with a Superconducting Qubit
• Resolving the energy levels of a nanomechanical oscillator
• Schrödinger cat states of a 16-microgram mechanical oscillator
• Quantum state preparation, tomography, and entanglement of mechanical oscillators
• Single-particle Mass Spectrometry with arrays of frequency-addressed nanomechanical resonators
• Parity measurement in the strong dispersive regime of circuit quantum acoustodynamics
• Developing a platform for linear mechanical quantum computing
• Dual-rail encoding with superconducting cavities
• Superconducting circuit quantum computing with nanomechanical resonators as storage
• Demonstrating a long-coherence dual-rail erasure qubit using tunable transmons
• Quantum erasure using entangled surface acoustic phonons
• Loss channels affecting lithium niobate phononic crystal resonators at cryogenic temperature
• Engineering Phonon-Qubit Interactions using Phononic Crystals