Photon Shot Noise Dephasing in the Strong-Dispersive Limit of Circuit QED

Abstract

We study the photon shot noise dephasing of a superconducting transmon qubit in the strong-dispersive limit, due to the coupling of the qubit to its readout cavity. As each random arrival or departure of a photon is expected to completely dephase the qubit, we can control the rate at which the qubit experiences dephasing events by varying \textit{in situ} the cavity mode population and decay rate. This allows us to verify a pure dephasing mechanism that matches theoretical predictions, and in fact explains the increased dephasing seen in recent transmon experiments as a function of cryostat temperature. We investigate photon dynamics in this limit and observe large increases in coherence times as the cavity is decoupled from the environment. Our experiments suggest that the intrinsic coherence of small Josephson junctions, when corrected with a single Hahn echo, is greater than several hundred microseconds.

5 pages, 4 figures; includes Supporting Online Material of 6 pages with 5 figures

References in corpus (18)

• Resolving photon number states in a superconducting circuit
• Superconducting qubit in waveguide cavity with coherence time approaching 0.1ms
• Suppressing Charge Noise Decoherence in Superconducting Charge Qubits
• Controlling the spontaneous emission of a superconducting transmon qubit
• AC-Stark Shift and Dephasing of a Superconducting Qubit Strongly Coupled to a Cavity Field
• Qubit-photon interactions in a cavity: Measurement induced dephasing and number splitting
• Coplanar Waveguide Resonators for Circuit Quantum Electrodynamics
• Black-box superconducting circuit quantization
• Quantum Non-demolition Detection of Single Microwave Photons in a Circuit
• High-Fidelity Readout in Circuit Quantum Electrodynamics Using the Jaynes-Cummings Nonlinearity
• Quasiparticle relaxation of superconducting qubits in the presence of flux
• Life after charge noise: recent results with transmon qubits
• Time-domain measurements of quasiparticle tunneling rates in a single-Cooper-pair transistor
• Low-frequency Noise in Josephson Junctions for Superconducting Qubits
• Impedance-matched low-pass stripline filters
• Millikelvin thermal and electrical performance of lossy transmission line filters
• Decoherence of floating qubits due to capacitive coupling
• Crossover from weak to strong coupling regime in dispersive circuit QED

Cited by in corpus (42)

• Confining the state of light to a quantum manifold by engineered two-photon loss
• Quantum Decoherence
• Quantum back-action of variable-strength measurement
• Measurement and Control of Quasiparticle Dynamics in a Superconducting Qubit
• Feedback control of a solid-state qubit using high-fidelity projective measurement
• Superconducting cavity qubit with tens of milliseconds single-photon coherence time
• Decoherence of superconducting qubits caused by quasiparticle tunneling
• Entanglement entropy scaling transition under competing monitoring protocols
• Photon Statistics of Propagating Thermal Microwaves
• High-Fidelity Measurement of a Superconducting Qubit using an On-Chip Microwave Photon Counter
• Quantum capacity and codes for the bosonic loss-dephasing channel
• Tunable-Cavity QED with Phase Qubits
• Photon-noise-tolerant dispersive readout of a superconducting qubit using a nonlinear Purcell filter
• Engineering the microwave to infrared noise photon flux for superconducting quantum systems
• Transition from Jaynes-Cummings to Autler-Townes ladder in a quantum dot-microcavity system
• On-demand driven dissipation for cavity reset and cooling
• Perturbative diagonalization for time-dependent strong interactions
• Timelessness strictly inside the Quantum Realm
• Numerical aspects of shot noise representation of infinitely divisible laws and related processes
• Efficient decoupling of a non-linear qubit mode from its environment
• Demonstrating efficient and robust bosonic state reconstruction via optimized excitation counting
• Nonequilibrium quasiparticle distribution in superconducting resonators: effect of pair-breaking photons
• Dephasing in Fluxonium Qubits from Coherent Quantum Phase Slips
• Quantify the Non-Markovian Process with Intervening Projections in a Superconducting Processor
• Collateral coupling between superconducting resonators: Fast and high fidelity generation of qudit-qudit entanglement
• The superconducting circuit companion -- an introduction with worked examples
• Parametric multi-element coupling architecture for coherent and dissipative control of superconducting qubits
• Copper waveguide cavities with reduced surface loss for coupling to superconducting qubits
• Optical Direct Write of Dolan--Niemeyer-Bridge Junctions for Transmon Qubits
• Noise-specific beats in the higher-level Ramsey curves of a transmon qubit
• Balanced cross-Kerr coupling for superconducting qubit readout
• Beyond-adiabatic Quantum Admittance of a Semiconductor Quantum Dot at High Frequencies: Rethinking Reflectometry as Polaron Dynamics
• Decoherence: From Interpretation to Experiment
• In situ mixer calibration for superconducting quantum circuits
• Violating Bell's inequality with an artificial atom and a cat state in a cavity
• A practical guide for building superconducting quantum devices
• Hybrid Quantum Interferometer in Bifurcation Mode as a Latching Quantum Readout
• Simple yet Accurate Stochastic Approach to the Quantum Phase Noise of Nanolasers
• Coherence-Mediated Quantum Thermometry in a Hybrid Circuit-QED Architecture
• Energetic cost of measurements using quantum, coherent, and thermal light
• Dynamics of a dispersively coupled transmon qubit in the presence of a noise source embedded in the control line
• Direct estimation of arbitrary observables of an oscillator