We describe a new kind of phase-preserving quantum amplifier which utilizes dissipative interactions in a parametrically coupled three-mode bosonic system. The use of dissipative interactions provides a fundamental advantage over standard cavity-based parametric amplifiers: large photon number gains are possible with quantum-limited added noise, with no limitation on the gain-bandwidth product. We show that the scheme is simple enough to be implemented both in optomechanical systems and in superconducting microwave circuits.
We describe a new kind of phase-preserving quantum amplifier which utilizes dissipative interactions in a parametrically coupled three-mode bosonic system. The use of dissipative interactions provides a fundamental advantage over standard cavity-based parametric amplifiers: large photon number gains are possible with quantum-limited added noise, with no limitation on the gain-bandwidth product. We show that the scheme is simple enough to be implemented both in optomechanical systems and in superconducting microwave circuits.
Isolation of a system from its environment is often desirable; however, dissipation can also be a useful resource. Remarkably, engineered dissipation enables the preparation and stabilization of quantum states of atoms, ions or superconducting qubits. This is achieved by a suitably engineered coupling to a dissipative cold reservoir formed by electromagnetic modes. Similarly, in the field of cavity electro- and optomechanics the control over mechanical oscillators utilizes the inherently cold dissipative nature of the electromagnetic degree of freedom. Breaking from this paradigm, recent theoretical work has considered the opposite regime in which the dissipation of the mechanical oscillator dominates and provides a cold dissipative reservoir to the electromagnetic mode. Here we report the experimental realization of this reversed dissipation regime in a microwave cavity optomechanical system and realize a quasi-instantaneous, cold reservoir for microwave light. We evidence this regime by decreasing or increasing the damping rate of the cavity on demand, that corresponds to amplification and de-amplification of the microwave field. Additionally, we observe the onset of parametric instability, i.e. the stimulated emission of microwaves (masing). Moreover, we employ the engineered cold reservoir to implement a low-noise, large-gain phase-preserving amplifier. Beyond offering the manipulation of microwave fields, such a dissipative reservoir for microwave light, when coupled to multiple cavity modes, forms the basis of microwave entanglement schemes, electromechanical amplifiers with unlimited gain-bandwidth product and dissipative quantum phase transitions. Equally important, combining such reservoir-mediated interaction with coherent dynamics allows for the realization of non-reciprocal devices, which would extend the available toolbox of quantum-limited microwave manipulation techniques.
We theoretically propose a scheme for realizing a quantum-limited directional amplifier in a triple-cavity optomechanical system, where one microwave cavity and two optical cavities are, respectively, coupled to a common mechanical resonator. Moreover, the two optical cavities are coupled directly to facilitate the directional amplification between microwave and optical photons. We find that directional amplification between the three cavity modes is achieved with two gain process and one conversion process, and the direction of amplification can be modulated by controlling the phase difference between the field-enhanced optomechanical coupling strengths. Furthermore, with increasing the optomechanical cooperativity, both gain and bandwidth of the directional amplifier can be enhanced, and the noise added to the amplifier can be suppressed to approach the standard quantum limit on the phase-preserving linear amplifier.
Abstract The investigation of the ultimate limits imposed by quantum mechanics on amplification represents an important topic both on a fundamental level and from the perspective of potential applications. We discuss here a novel regime for bosonic linear amplifiers—beside phase-insensitive and phase-sensitive amplification—which we term here phase-mixing amplification. Furthermore, we show that phase-mixing amplification can be realised in a cavity optomechanical setup, constituted by a mechanical resonator which is dispersively coupled to an optomechanical cavity asymmetrically driven around both mechanical sidebands. While, in general, this amplifier is phase-mixing, for a suitable choice of parameters, the amplifier proposed here operates as a phase-sensitive amplifier. We show that both configurations allow amplification with an added noise below the quantum limit of (phase-insensitive) amplification in a parameter range compatible with current experiments in microwave circuit optomechanics. In particular, we show that introducing phase-mixing amplification typically allows for a significant reduction of the added noise.
We study the directional phase-sensitive amplification between microwave and optical photons in a triple-cavity optomechanical system consisting of three cavities and one mechanical resonator. When the microwave cavity is pumped on both red and blue sidebands but the directly coupled optical cavities are only pumped on the red sidebands, directional phase-sensitive amplification can be realized by tuning the effective optomechanical couplings and the coupling strength between the optical cavities. We show that both gain and bandwidth of the amplifier can be enhanced by increasing the optomechanical cooperativities, indicating an unlimited gain-bandwidth product. Meanwhile, the proposed phase-sensitive amplifier can approach the quantum limit of zero added noise in the large cooperativity limit.
Quantum parametric amplifiers typically generate by operating in proximity to a point of dynamical instability. We consider an alternate general strategy where quantum-limited, large-gain amplification is achieved without any proximity to a dynamical instability. Our basic mechanism (involving dynamics that conserves the number of squeezed photons) enables the design of a variety of one and two mode amplifiers that are not limited by any fundamental gain-bandwidth constraint. We focus on a particular realization that allows us to realize an ideal single-mode squeezing operation in transmission, and which has zero reflection. We present both a thorough theoretical analysis of this system (including pump-depletion effects), and also discuss results of an experimental superconducting quantum circuit implementation.
Josephson parametric amplifiers (JPAs) approaching quantum-limited noise performance have been instrumental in enabling high fidelity readout of superconducting qubits and, recently, semiconductor quantum dots (QDs). We propose that the quantum capacitance arising in electronic two-level systems (the dual of Josephson inductance) can provide an alternative dissipation-less non-linear element for parametric amplification. We experimentally demonstrate phase-sensitive parametric amplification using a QD-reservoir electron transition in a CMOS nanowire split-gate transistor embedded in a 1.8~GHz superconducting lumped-element microwave cavity, achieving parametric gains of -3 to +3 dB, limited by Sisyphus dissipation. Using a semi-classical model, we find an optimised design within current technological capabilities could achieve gains and bandwidths comparable to JPAs, while providing complementary specifications with respect to integration in semiconductor platforms or operation at higher magnetic fields.