Multimode Purcell Filter for Superconducting-Qubit Reset and Readout with Intrinsic Purcell Protection

Abstract

Efficient qubit reset and leakage reduction are essential for scalable superconducting quantum computing, particularly in the context of quantum error correction. However, such operations often require additional on-chip components. Here, we propose and experimentally demonstrate a hardware-efficient approach to qubit reset and readout using a multi-mode Purcell filter in a superconducting quantum circuit. We exploit the inherent multi-mode structure of a coplanar waveguide resonator, using its fundamental and second-order modes for qubit reset and readout, respectively, thereby avoiding additional components. Implemented in a flip-chip architecture, our device achieves unconditional reset with residual excitation below 1\% in 220 ns, and a leakage reduction unit that selectively resets the second excited state within 62 ns with a residual $|f⟩$ population of 6.1\%, accounting for the readout error. Despite the qubits being directly coupled to the filter in our configuration, the measured relaxation times are not degraded owing to intrinsic Purcell protection provided by an auxiliary mode. To our knowledge, this is the first experimental trial that exploits different-order modes of a microwave resonator for distinct qubit operations, representing a new direction toward scalable, hardware-efficient quantum processor design.

Accepted version. Published in Phys. Rev. Applied 25, 044003 (2026)

References in corpus (62)

• Charge insensitive qubit design derived from the Cooper pair box
• Surface codes: Towards practical large-scale quantum computation
• Circuit Quantum Electrodynamics
• Suppressing quantum errors by scaling a surface code logical qubit
• Quantum error correction below the surface code threshold
• Amplification and squeezing of quantum noise with a tunable Josephson metamaterial
• Realization of Three-Qubit Quantum Error Correction with Superconducting Circuits
• New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds
• Controlling the spontaneous emission of a superconducting transmon qubit
• Planar Superconducting Resonators with Internal Quality Factors above One Million
• Qubit-photon interactions in a cavity: Measurement induced dephasing and number splitting
• Exponential suppression of bit or phase flip errors with repetitive error correction
• Transmon qubit with relaxation time exceeding 0.5 milliseconds
• Realizing Rapid, High-Fidelity, Single-Shot Dispersive Readout of Superconducting Qubits
• Deterministic Quantum State Transfer and Generation of Remote Entanglement using Microwave Photons
• Dispersive regime of circuit QED: photon-dependent qubit dephasing and relaxation rates
• Single-shot qubit readout in circuit Quantum Electrodynamics
• Single-shot qubit readout in circuit Quantum Electrodynamics
• Fast Reset and Suppressing Spontaneous Emission of a Superconducting Qubit
• Rapid high-fidelity multiplexed readout of superconducting qubits
• Microwave Quantum Link between Superconducting Circuits Housed in Spatially Separated Cryogenic Systems
• On-demand quantum state transfer and entanglement between remote microwave cavity memories
• Fast and Unconditional All-Microwave Reset of a Superconducting Qubit
• Deterministic multi-qubit entanglement in a quantum network
• Quantum limited amplification and entanglement in coupled nonlinear resonators
• Deterministic remote entanglement of superconducting circuits through microwave two-photon transitions
• Thermal and Residual Excited-State Population in a 3D Transmon Qubit
• Strong environmental coupling in a Josephson parametric amplifier
• First-order sideband transitions with flux-driven asymmetric transmon qubits
• Fast readout and reset of a superconducting qubit coupled to a resonator with an intrinsic Purcell filter
• Removing leakage-induced correlated errors in superconducting quantum error correction
• Systematic Improvements in Transmon Qubit Coherence Enabled by Niobium Surface Encapsulation
• Entangled state preparation via dissipation-assisted adiabatic passages
• Quantum theory of a bandpass Purcell filter for qubit readout
• Measurement-induced qubit state mixing in circuit QED from up-converted dephasing noise
• Low-loss interconnects for modular superconducting quantum processors
• Rapid Driven Reset of a Qubit Readout Resonator
• Overcoming leakage in scalable quantum error correction
• 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
• Error-detected state transfer and entanglement in a superconducting quantum network
• Measurement-Induced Transmon Ionization
• Enhancing Dispersive Readout of Superconducting Qubits Through Dynamic Control of the Dispersive Shift: Experiment and Theory
• Synthesis of parametrically-coupled networks
• Exceptional entanglement phenomena: non-Hermiticity meeting non-classicality
• All-microwave leakage reduction units for quantum error correction with superconducting transmon qubits
• A hardware-efficient leakage-reduction scheme for quantum error correction with superconducting transmon qubits
• Deterministic quantum teleportation between distant superconducting chips
• Reducing Spontaneous Emission in Circuit Quantum Electrodynamics by a Combined Readout/Filter Technique
• Photon-noise-tolerant dispersive readout of a superconducting qubit using a nonlinear Purcell filter
• Fast multiplexed superconducting qubit readout with intrinsic Purcell filtering
• Fast Flux-Activated Leakage Reduction for Superconducting Quantum Circuits
• Coupler-Assisted Leakage Reduction for Scalable Quantum Error Correction with Superconducting Qubits
• Broadband Bandpass Purcell Filter for Circuit Quantum Electrodynamics
• 99.9%-fidelity in measuring a superconducting qubit
• Multi-Purpose Architecture for Fast Reset and Protective Readout of Superconducting Qubits
• Interferometric Purcell suppression of spontaneous emission in a superconducting qubit
• Demonstrating quantum error mitigation on logical qubits
• A thermal-noise-resilient microwave quantum network traversing 4 K
• Prethermalization by Random Multipolar Driving on a 78-Qubit Superconducting Processor
• Balanced cross-Kerr coupling for superconducting qubit readout
• One- and two-dimensional cluster states for topological phase simulation and measurement-based quantum computation