A Tunable Coupler with ScS Quantum Point Contact to Mediate Strong Interaction Between Flux Qubits

Soroka, A. A.

doi:10.1007/s10909-013-0873-y

Cited by 3 publications

(1 citation statement)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the upper level E 1 the tunneling rate increases by a factor of approximately 10 3 . The potential and energy levels are calculated by solving the Schrödinger equation (by the method described in detail in the work [8]) with the following parameters: qubit inductance L q = 240 pH, critical current of the Josephson junction I c = 2.01 µA, SIS junction capacitance C = 0.32 pF, and dimensionless para-…”

Section: Introductionmentioning

confidence: 99%

An RF SQUID readout for a flux qubit-based microwave single photon counter

Shapovalov¹,

Lyakhno²,

Kalenyuk³

et al. 2023

Supercond. Sci. Technol.

View full text Add to dashboard Cite

An analysis of the measurement of the magnetic flux in superconducting qubits based on RF SQUIDs was carried out with a 800 MHz bandwidth low power consumption cryogenic high-electron-mobility transistor (HEMT) amplifier. The preliminary experimental results obtained at temperatures 2 K and 4 K for RF SQUIDs in hysteretic and in two non-hysteretic regimes with a pump frequency of about $30$~MHz are discussed. Parameters of RF SQUIDs in the hysteretic and non-hysteretic modes are analyzed within the framework of the Resistively and Capacitively Shunted Junction (RCSJ) model for Josephson junctions. Its sensitivity at the temperature of 30 mK and frequency band (speed) are calculated and optimized to read the states of a flux qubit used as single microwave photon counter. It is shown that an RF SQUID, operated in an adiabatic non-hysteretic mode for qubit readout, allows to minimize its back-action effect and the dark count rate. This is owing to the absence of Josephson generation, the small amplitude of the resonator electromagnetic field, and the selection of the pump frequency that does not coincide with the characteristic frequencies of the flux qubit.

show abstract

Section: Introductionmentioning

confidence: 99%

An RF SQUID readout for a flux qubit-based microwave single photon counter

Shapovalov¹,

Lyakhno²,

Kalenyuk³

et al. 2023

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

Phase stability and temperature effect in ScX (X=S, Se and Te) compounds

et al. 2020

View full text Add to dashboard Cite

Isolation of a Josephson qubit from the electromagnetic environment

Korolev

Турутанов

Shulga

et al. 2015

Low Temperature Physics

View full text Add to dashboard Cite

We consider two aspects of isolation of a Josephson flux (charge-flux) qubit from the external dissipative electromagnetic environment: (i) selecting an optimal topology of the superconducting qubit circuit and (ii) passive filtering of Planck radiation at the input of the qubit-state detection circuit. When reading the state of a macroscopic quantum object (“Schrödinger's cat”) with the weak continuous measurement technique, the coupling to the environment, both direct and through the connected circuits, is the cause of the rapid loss of coherence of the superposition states. The coefficients of coupling to the external electromagnetic environment are discussed, as well as the problem of their minimization for flat (2D) and bulk (3D) designs of the qubit quantization loops. The analysis of the characteristics of low-temperature combined broadband filters designed to effectively reduce the electromagnetic noise in the control and measurement circuits is carried out. It is shown experimentally that a cryogenic Cu–CuO powder filter installed directly into the measuring circuit results in a significant suppression of the back action of a cooled HEMT amplifier to the qubit.

show abstract

A Tunable Coupler with ScS Quantum Point Contact to Mediate Strong Interaction Between Flux Qubits

Cited by 3 publications

References 30 publications

An RF SQUID readout for a flux qubit-based microwave single photon counter

An RF SQUID readout for a flux qubit-based microwave single photon counter

Phase stability and temperature effect in ScX (X=S, Se and Te) compounds

Isolation of a Josephson qubit from the electromagnetic environment

Contact Info

Product

Resources

About