Detecting quasiparticle tunneling events in superconducting circuits provides information about the population and dynamics of non-equilibrium quasiparticles. Such events can be detected by monitoring changes in the frequency of an offset-charge-sensitive superconducting qubit. This monitoring has so far been performed by Ramsey interferometry assisted by a readout resonator. Here, we demonstrate a quasiparticle detector based on a superconducting qubit directly coupled to a waveguide. We directly measure quasiparticle number parity on the qubit island by probing the coherent scattering of a microwave tone, offering simplicity of operation, fast detection speed, and a large signal-to-noise ratio. We observe tunneling rates between 0.8 and $7~\rm{s}^{-1}$ , depending on the average occupation of the detector qubit, and achieve a temporal resolution below $10~μ\rm{s}$ without a quantum-limited amplifier. Our simple and efficient detector lowers the barrier to perform studies of quasiparticle population and dynamics, facilitating progress in fundamental science, quantum information processing, and sensing.Detecting quasiparticle tunneling events in superconducting circuits provides information about the population and dynamics of non-equilibrium quasiparticles. Such events can be detected by monitoring changes in the frequency of an offset-charge-sensitive superconducting qubit. This monitoring has so far been performed by Ramsey interferometry assisted by a readout resonator. Here, we demonstrate a quasiparticle detector based on a superconducting qubit directly coupled to a waveguide. We directly measure quasiparticle number parity on the qubit island by probing the coherent scattering of a microwave tone, offering simplicity of operation, fast detection speed, and a large signal-to-noise ratio. We observe tunneling rates between 0.8 and $7~\rm{s}^{-1}$, depending on the average occupation of the detector qubit, and achieve a temporal resolution below $10~μ\rm{s}$ without a quantum-limited amplifier. Our simple and efficient detector lowers the barrier to perform studies of quasiparticle population and dynamics, facilitating progress in fundamental science, quantum information processing, and sensing.

arXiv:2404.01277Apr 1, 20241 citation

Quasiparticle statistics from the ground state wave function

Julia Wildeboer

Bulletin of the American Physical SocietyMar 14, 20170 citations

Melting a Rydberg ice to a topological spin liquid with cavity vacuum fluctuation

H. R. Kong, Taylor, J., Dong, Y. +1 more

Quantum spin liquids are exotic phases of matter that are prevented from being frozen even at zero temperature, and appear disordered by local probes that monitor the subsystems. Driven by quantum fluctuations, topological spin liquids are manifested by their long-range entanglement, and are characterized by quasiparticles with fractional statistics. Here, we make contact of a 2D Rydberg ice to a QED vacuum of an ultra-high-finesse optical cavity, and dynamically promote the frustrated background field of the spin ice to a $\mathbb{Z}_2$ spin liquid. We characterize the deconfined nature of the dynamical gauge theory residing in the strongly-correlated Rydberg matter with Wilsonian loops. We observe the proliferation of vison and spinon pairs by site-resolved fluorescence imaging, and detect the exchange statistical angle $θ_{\text{top}}\simπ/2$ between the two anyons by monitoring the dynamical correlators of the fluctuating cavity photons. Our work provides the first microscopic detection of anyons in a topological quantum matter, and heralds the arrival of strongly-coupled many-body QED, where interacting matter and light are put on equal footing at the level of individual quanta.Quantum spin liquids are exotic phases of matter that are prevented from being frozen even at zero temperature, and appear disordered by local probes that monitor the subsystems. Driven by quantum fluctuations, topological spin liquids are manifested by their long-range entanglement, and are characterized by quasiparticles with fractional statistics. Here, we make contact of a 2D Rydberg ice to a QED vacuum of an ultra-high-finesse optical cavity, and dynamically promote the frustrated background field of the spin ice to a $\mathbb{Z}_2$ spin liquid. We characterize the deconfined nature of the dynamical gauge theory residing in the strongly-correlated Rydberg matter with Wilsonian loops. We observe the proliferation of vison and spinon pairs by site-resolved fluorescence imaging, and detect the exchange statistical angle $θ_{\text{top}}\simπ/2$ between the two anyons by monitoring the dynamical correlators of the fluctuating cavity photons. Our work provides the first microscopic detection of anyons in a topological quantum matter, and heralds the arrival of strongly-coupled many-body QED, where interacting matter and light are put on equal footing at the level of individual quanta.

arXiv:2109.03741Sep 8, 20210 citations

On a quantum statistics of quasiparticles

M. Ya. Azbel

Physics Letters ASep 1, 19761 citation

7~\rm{s}^{-1}

, depending on the average occupation of the detector qubit, and achieve a temporal resolution below

10~μ\rm{s}

without a quantum-limited amplifier. Our simple and efficient detector lowers the barrier to perform studies of quasiparticle population and dynamics, facilitating progress in fundamental science, quantum information processing, and sensing.

\mathbb{Z}_2

spin liquid. We characterize the deconfined nature of the dynamical gauge theory residing in the strongly-correlated Rydberg matter with Wilsonian loops. We observe the proliferation of vison and spinon pairs by site-resolved fluorescence imaging, and detect the exchange statistical angle

θ_{\text{top}}\simπ/2

between the two anyons by monitoring the dynamical correlators of the fluctuating cavity photons. Our work provides the first microscopic detection of anyons in a topological quantum matter, and heralds the arrival of strongly-coupled many-body QED, where interacting matter and light are put on equal footing at the level of individual quanta.