956 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- The University of TokyoJP24 papers
- RIKEN Center for Emergent Matter ScienceJP16 papers
- University of Wisconsin–MadisonUS16 papers
- NEC (Japan)JP11 papers
- Kyushu UniversityJP10 papers
- Japan Science and Technology AgencyJP7 papers
- Kindai UniversityJP6 papers
- RIKENJP6 papers
- Aalto UniversityFI4 papers
- MIT Lincoln LaboratoryUS4 papers
- National Institute of Advanced Industrial Science and TechnologyJP4 papers
- National Institute of Information and Communications TechnologyJP4 papers
30 papers · 1 filter
Diamond optomechanical cavity with a color center for microwave-to-optical quantum interfaces
Byunggi Kim, Hodaka Kurokawa, Katsuta Sakai +3
Quantum transduction between microwave and optical photons plays a key role in quantum communication among remote qubits. Although the quantum transduction schemes generating commu…
Efficient numerical approach for the simulations of high-power dispersive readout with time-dependent unitary transformation
Shimpei Goto, Kazuki Koshino
We develop an efficient numerical approach for simulating the high-power dispersive readout in circuit quantum electrodynamics. In the numerical simulations of the high-power reado…
Demonstration of deterministic SWAP gate between superconducting and frequency-encoded microwave-photon qubits
Kazuki Koshino, Kunihiro Inomata
The number of superconducting qubits contained in a single quantum processor is increasing steadily. However, to realize a truly useful quantum computer, it is inevitable to increa…
Evaluating thermal expectation values by almost ideal sampling with Trotter gates
Shimpei Goto, Ryui Kaneko, Ippei Danshita
We investigate the sampling efficiency for the simulations of quantum many-body systems at finite temperatures when initial sampling states are generated by applying Trotter gates…
Saturable Purcell filter for circuit quantum electrodynamics
Ivan Iakoupov, Kazuki Koshino
We consider a typical circuit QED setup where an artificial atom encodes a qubit and is dispersively coupled to a measurement resonator that in turn is coupled to a transmission li…
Deterministic three-photon down-conversion by a passive ultrastrong cavity-QED system
Kazuki Koshino, Tomohiro Shitara, Ziqiao Ao +1
In ultra- and deep-strong cavity quantum electrodynamics (QED) systems, many intriguing phenomena that do not conserve the excitation number are expected to occur. In this study, w…
Elliptical rotation of cavity amplitude in ultrastrong waveguide QED
Kazuki Koshino
We investigate optical response of a linear waveguide quantum electrodynamics (QED) system, namely, an optical cavity coupled to a waveguide. Our analysis is based on exact diagona…
Spectroscopic observation of the crossover from a classical Duffing oscillator to a Kerr parametric oscillator
T. Yamaji, S. Kagami, A. Yamaguchi +6
We study microwave response of a Josephson parametric oscillator consisting of a superconducting transmission-line resonator with an embedded dc-SQUID. The dc-SQUID allows to contr…
Effects of higher levels of qubits on control of qubit protected by a Josephson quantum filter
Shumpei Masuda, Kazuki Koshino
A Josephson quantum filter (JQF) protects a data qubit (DQ) from the radiative decay into transmission lines in superconducting quantum computing architectures. A transmon, which i…
Nonclassicality of open circuit QED systems in the deep-strong coupling regime
Tomohiro Shitara, Motoaki Bamba, Fumiki Yoshihara +4
We investigate theoretically how the ground state of a qubit-resonator system in the deep-strong coupling (DSC) regime is affected by the coupling to an environment. We employ as a…
Fast parametric two-qubit gates with suppressed residual interaction using a parity-violated superconducting qubit
Atsushi Noguchi, Alto Osada, Shumpei Masuda +7
We demonstrate fast two-qubit gates using a parity-violated superconducting qubit consisting of a capacitively-shunted asymmetric Josephson-junction loop under a finite magnetic fl…
Breaking the trade-off between fast control and long lifetime of a superconducting qubit
Shingo Kono, Kazuki Koshino, Dany Lachance-Quirion +4
The rapid development in designs and fabrication techniques of superconducting qubits has helped making coherence times of qubits longer. In the near future, however, the radiative…
On-demand generation and characterization of a microwave time-bin qubit
Jesper Ilves, Shingo Kono, Yoshiki Sunada +4
Superconducting circuits offer a scalable platform for the construction of large-scale quantum networks where information can be encoded in multiple temporal modes of propagating m…
Protection of a qubit with a subradiance effect: Josephson quantum filter
Kazuki Koshino, Shingo Kono, Yasunobu Nakamura
The coupling between a superconducting qubit and a control line inevitably results in radiative decay of the qubit into the line. We propose a Josephson quantum filter (JQF), which…
Calibration of cryogenic amplification chains using normal-metal--insulator--superconductor junctions
Eric Hyyppä, Máté Jenei, Shumpei Masuda +7
Various applications of quantum devices call for an accurate calibration of cryogenic amplification chains. To this end, we present a convenient calibration scheme and use it to ac…
Inversion of Qubit Energy Levels in Qubit-Oscillator Circuits in the Deep-Strong-Coupling Regime
Fumiki Yoshihara, Tomoko Fuse, Ziqiao Ao +6
We report on experimentally measured light shifts of superconducting flux qubits deep-strongly coupled to LC oscillators, where the coupling constants are comparable to the qubit a…
Quantum non-demolition detection of an itinerant microwave photon
S. Kono, K. Koshino, Y. Tabuchi +2
Photon detectors are an elementary tool to measure electromagnetic waves at the quantum limit and are heavily demanded in the emerging quantum technologies such as communication, s…
Fast forward of adiabatic spin dynamics of entangled states
Iwan Setiawan, Bobby Eka Gunara, Shumpei Masuda +1
We develop a scheme of fast forward of adiabatic spin dynamics of quantum entangled states. We settle the quasi-adiabatic dynamics by adding the regularization terms to the origina…
Nonclassical photon number distribution in a superconducting cavity under a squeezed drive
S. Kono, Y. Masuyama, T. Ishikawa +5
A superconducting qubit in the strong dispersive regime of a circuit quantum electrodynamics system is a powerful probe for microwave photons in a cavity mode. In this regime, a qu…
Tunable quantum gate between a superconducting atom and a propagating microwave photon
K. Koshino, K. Inomata, Z. R. Lin +3
We propose a two-qubit quantum logic gate between a superconducting atom and a propagating microwave photon. The atomic qubit is encoded on its lowest two levels and the photonic q…
Single microwave-photon detector using an artificial -type three-level system
Kunihiro Inomata, Zhirong Lin, Kazuki Koshino +4
Single photon detection is a requisite technique in quantum-optics experiments in both the optical and the microwave domains. However, the energy of microwave quanta are four to fi…
Dressed-state engineering for continuous detection of itinerant microwave photons
Kazuki Koshino, Zhirong Lin, Kunihiro Inomata +2
We propose a scheme for continuous detection of itinerant microwave photons in circuit quantum electrodynamics. In the proposed device, a superconducting qubit is coupled dispersiv…
Theory of microwave single-photon detection using an impedance-matched system
Kazuki Koshino, Kunihiro Inomata, Zhirong Lin +2
By properly driving a qubit-resonator system in the strong dispersive regime, we implement an "impedance-matched" system in the dressed states, where a resonant single photon d…
Josephson parametric phase-locked oscillator and its application to dispersive readout of superconducting qubits
Z. R. Lin, K. Inomata, K. Koshino +4
The parametric phase-locked oscillator (PPLO), also known as a parametron, is a resonant circuit in which one of the reactances is periodically modulated. It can detect, amplify, a…