Two-qubit parametric amplifier: large amplification of weak signals

Abstract

Using numerical simulations, we show that two coupled qubits can amplify a weak signal about hundredfold. This can be achieved if the two qubits are biased simultaneously by this weak signal and a strong pump signal, both of which having frequencies close to the inter-level transitions in the system. The weak signal strongly affects the spectrum generated by the strong pumping drive by producing and controlling mixed harmonics with amplitudes of the order of the main harmonic of the strong drive. We show that the amplification is robust with respect to noise, with an intensity of the order of the weak signal. When deviating from the optimal regime (corresponding to strong qubit coupling and a weak-signal frequency equal to the inter-level transition frequency) the proposed amplifier becomes less efficient, but it can still considerably enhance a weak signal (by several tens). We therefore propose to use coupled qubits as a combined parametric amplifier and frequency shifter.

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References in corpus (12)

• Atomic physics and quantum optics using superconducting circuits
• Superconducting Circuits and Quantum Information
• The dynamical Casimir effect in superconducting microwave circuits
• Controllable coupling of superconducting flux qubits
• Tuning the Gap of a Superconducting Flux Qubit
• Quantum metamaterials: Electromagnetic waves in a Josephson qubit line
• Interqubit coupling mediated by a high-excitation-energy quantum object
• Switchable resonant coupling of flux qubits
• Direct Josephson coupling between superconducting flux qubits
• Modelling chemical reactions using semiconductor quantum dots
• Generalized switchable coupling for superconducting qubits using double resonance
• Noise-spectroscopy of multiqubit systems: Determining all their parameters by applying an external classical noise

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• Quantum electrodynamics of non-demolition detection of single microwave photon by superconducting qubit array
• Entangling continuous variables with a qubit array