Transmon-qubit readout using in-situ bifurcation amplification in the mesoscopic regime

Abstract

We demonstrate a transmon qubit readout based on the nonlinear response to a drive of polaritonic meters in-situ coupled to the qubit. Inside a 3D readout cavity, we place a transmon molecule consisting of a transmon qubit and an ancilla mode interacting via non-perturbative cross-Kerr coupling. The cavity couples strongly only to the ancilla mode, leading to hybridized lower and upper polaritonic meters. Both polaritons are anharmonic and dissipative, as they inherit a self-Kerr nonlinearity $U$ from the ancilla and effective decay $\kappa$ from the open cavity. Via the ancilla, the polariton meters also inherit the non-perturbative cross-Kerr coupling to the qubit. This results in a high qubit-dependent displacement $2\chi >\kappa ,U$ that can be read out via the cavity without causing Purcell decay. Moreover, the polariton meters, being nonlinear resonators, present bistability, and bifurcation behavior when the probing power increases. In this work, we focus on the bifurcation at low power in the few-photon regime, called the mesoscopic regime, which is accessible when the self-Kerr and decay rates of the polariton meter are similar $U\sim \kappa$. Capitalizing on a latching mechanism by bifurcation, the readout is sensitive to transmon qubit relaxation error only in the first tens of nanoseconds. We thus report a single-shot fidelity of 98.6 $\%$ while having an integration time of a 500 ns and no requirement for an external quantum-limited amplifier.

References in corpus (47)

• Charge insensitive qubit design derived from the Cooper pair box
• Cavity quantum electrodynamics for superconducting electrical circuits: an architecture for quantum computation
• Suppressing quantum errors by scaling a surface code logical qubit
• Realizing Repeated Quantum Error Correction in a Distance-Three Surface Code
• Controlling the spontaneous emission of a superconducting transmon qubit
• Realizing Rapid, High-Fidelity, Single-Shot Dispersive Readout of Superconducting Qubits
• To catch and reverse a quantum jump mid-flight
• Quantum Non-demolition Detection of Single Microwave Photons in a Circuit
• Single-shot qubit readout in circuit Quantum Electrodynamics
• Single-shot qubit readout in circuit Quantum Electrodynamics
• High-Fidelity Readout in Circuit Quantum Electrodynamics Using the Jaynes-Cummings Nonlinearity
• Rapid high-fidelity multiplexed readout of superconducting qubits
• Measurement-induced state transitions in a superconducting qubit: Beyond the rotating wave approximation
• Quantum limited amplification and entanglement in coupled nonlinear resonators
• Dispersive measurements of superconducting qubit coherence with a fast, latching readout
• Fast readout and reset of a superconducting qubit coupled to a resonator with an intrinsic Purcell filter
• Characterization of a two-transmon processor with individual single-shot qubit readout
• High-contrast dispersive readout of a superconducting flux qubit using a nonlinear resonator
• Single-shot Readout of a Superconducting Qubit using a Josephson Parametric Oscillator
• Matching and maximum likelihood decoding of a multi-round subsystem quantum error correction experiment
• Dynamics of Transmon Ionization
• Circuit QED with a Nonlinear Resonator : ac-Stark Shift and Dephasing
• Transmon qubit readout fidelity at the threshold for quantum error correction without a quantum-limited amplifier
• High-fidelity measurement of qubits encoded in multilevel superconducting circuits
• Fast high fidelity quantum non-demolition qubit readout via a non-perturbative cross-Kerr coupling
• Non-degenerate parametric amplifiers based on dispersion engineered Josephson junction arrays
• Implementation of pairwise longitudinal coupling in a three-qubit superconducting circuit
• Quantum non-demolition dispersive readout of a superconducting artificial atom using large photon numbers
• Backaction of a driven nonlinear resonator on a superconducting qubit
• Quantum Heating of a nonlinear resonator probed by a superconducting qubit
• High-efficiency measurement of an artificial atom embedded in a parametric amplifier
• Multiplexed Readout of Transmon Qubits with Josephson Bifurcation Amplifiers
• Rabi-like oscillations of an anharmonic oscillator: classical versus quantum interpretation
• Bistability in a Mesoscopic Josephson Junction Array Resonator
• Ideal Quantum Nondemolition Readout of a Flux Qubit Without Purcell Limitations
• Efficient and Low-Backaction Quantum Measurement Using a Chip-Scale Detector
• Quantum versus classical switching dynamics of driven-dissipative Kerr resonators
• Ultrafast QND measurements based on diamond-shape artificial atom
• Quantum Time-evolution in Qubit Readout Process with a Josephson Bifurcation Amplifier
• Weak Qubit Measurement with a Nonlinear Cavity: Beyond Perturbation Theory
• A V-shape superconducting artificial atom based on two inductively coupled transmons
• Superconducting qubits beyond the dispersive regime
• Exact quantization of superconducting circuits
• Parallel tomography of quantum non-demolition measurements in multi-qubit devices
• Multi-mode superconducting circuits for realizing strongly coupled multi-qubit processor units
• Complete physical characterization of QND measurements via tomography
• In-situ tunable nonlinearity and competing signal paths in coupled superconducting resonators

Cited by in corpus (2)

• Efficient decoupling of a non-linear qubit mode from its environment
• Parametric multi-element coupling architecture for coherent and dissipative control of superconducting qubits