@article{11353,
abstract = {Micro- and nanoscale optical or microwave cavities are used in a wide range of classical applications and quantum science experiments, ranging from precision measurements, laser technologies to quantum control of mechanical motion. The dissipative photon loss via absorption, present to some extent in any optical cavity, is known to introduce thermo-optical effects and thereby impose fundamental limits on precision measurements. Here, we theoretically and experimentally reveal that such dissipative photon absorption can result in quantum feedback via in-loop field detection of the absorbed optical field, leading to the intracavity field fluctuations to be squashed or antisquashed. A closed-loop dissipative quantum feedback to the cavity field arises. Strikingly, this modifies the optical cavity susceptibility in coherent response measurements (capable of both increasing or decreasing the bare cavity linewidth) and causes excess noise and correlations in incoherent interferometric optomechanical measurements using a cavity, that is parametrically coupled to a mechanical oscillator. We experimentally observe such unanticipated dissipative dynamics in optomechanical spectroscopy of sideband-cooled optomechanical crystal cavitiess at both cryogenic temperature (approximately 8 K) and ambient conditions. The dissipative feedback introduces effective modifications to the optical cavity linewidth and the optomechanical scattering rate and gives rise to excess imprecision noise in the interferometric quantum measurement of mechanical motion. Such dissipative feedback differs fundamentally from a quantum nondemolition feedback, e.g., optical Kerr squeezing. The dissipative feedback itself always results in an antisqueezed out-of-loop optical field, while it can enhance the coexisting Kerr squeezing under certain conditions. Our result applies to cavity spectroscopy in both optical and superconducting microwave cavities, and equally applies to any dissipative feedback mechanism of different bandwidth inside the cavity. It has wide-ranging implications for future dissipation engineering, such as dissipation enhanced sideband cooling and Kerr squeezing, quantum frequency conversion, and nonreciprocity in photonic systems.},
author = {Qiu, Liu and Huang, Guanhao and Shomroni, Itay and Pan, Jiahe and Seidler, Paul and Kippenberg, Tobias J.},
issn = {26913399},
journal = {PRX Quantum},
number = {2},
publisher = {American Physical Society},
title = {{Dissipative quantum feedback in measurements using a parametrically coupled microcavity}},
doi = {10.1103/PRXQuantum.3.020309},
volume = {3},
year = {2022},
}
@article{7910,
abstract = {Quantum illumination uses entangled signal-idler photon pairs to boost the detection efficiency of low-reflectivity objects in environments with bright thermal noise. Its advantage is particularly evident at low signal powers, a promising feature for applications such as noninvasive biomedical scanning or low-power short-range radar. Here, we experimentally investigate the concept of quantum illumination at microwave frequencies. We generate entangled fields to illuminate a room-temperature object at a distance of 1 m in a free-space detection setup. We implement a digital phase-conjugate receiver based on linear quadrature measurements that outperforms a symmetric classical noise radar in the same conditions, despite the entanglement-breaking signal path. Starting from experimental data, we also simulate the case of perfect idler photon number detection, which results in a quantum advantage compared with the relative classical benchmark. Our results highlight the opportunities and challenges in the way toward a first room-temperature application of microwave quantum circuits.},
author = {Barzanjeh, Shabir and Pirandola, S. and Vitali, D and Fink, Johannes M},
issn = {23752548},
journal = {Science Advances},
number = {19},
publisher = {AAAS},
title = {{Microwave quantum illumination using a digital receiver}},
doi = {10.1126/sciadv.abb0451},
volume = {6},
year = {2020},
}
@article{8038,
abstract = {Microelectromechanical systems and integrated photonics provide the basis for many reliable and compact circuit elements in modern communication systems. Electro-opto-mechanical devices are currently one of the leading approaches to realize ultra-sensitive, low-loss transducers for an emerging quantum information technology. Here we present an on-chip microwave frequency converter based on a planar aluminum on silicon nitride platform that is compatible with slot-mode coupled photonic crystal cavities. We show efficient frequency conversion between two propagating microwave modes mediated by the radiation pressure interaction with a metalized dielectric nanobeam oscillator. We achieve bidirectional coherent conversion with a total device efficiency of up to ~60%, a dynamic range of 2 × 10^9 photons/s and an instantaneous bandwidth of up to 1.7 kHz. A high fidelity quantum state transfer would be possible if the drive dependent output noise of currently ~14 photons s^−1 Hz^−1 is further reduced. Such a silicon nitride based transducer is in situ reconfigurable and could be used for on-chip classical and quantum signal routing and filtering, both for microwave and hybrid microwave-optical applications.},
author = {Fink, Johannes M and Kalaee, M. and Norte, R. and Pitanti, A. and Painter, O.},
issn = {20589565},
journal = {Quantum Science and Technology},
number = {3},
publisher = {IOP Publishing},
title = {{Efficient microwave frequency conversion mediated by a photonics compatible silicon nitride nanobeam oscillator}},
doi = {10.1088/2058-9565/ab8dce},
volume = {5},
year = {2020},
}
@article{8529,
abstract = {Practical quantum networks require low-loss and noise-resilient optical interconnects as well as non-Gaussian resources for entanglement distillation and distributed quantum computation. The latter could be provided by superconducting circuits but existing solutions to interface the microwave and optical domains lack either scalability or efficiency, and in most cases the conversion noise is not known. In this work we utilize the unique opportunities of silicon photonics, cavity optomechanics and superconducting circuits to demonstrate a fully integrated, coherent transducer interfacing the microwave X and the telecom S bands with a total (internal) bidirectional transduction efficiency of 1.2% (135%) at millikelvin temperatures. The coupling relies solely on the radiation pressure interaction mediated by the femtometer-scale motion of two silicon nanobeams reaching a Vπ as low as 16 μV for sub-nanowatt pump powers. Without the associated optomechanical gain, we achieve a total (internal) pure conversion efficiency of up to 0.019% (1.6%), relevant for future noise-free operation on this qubit-compatible platform.},
author = {Arnold, Georg M and Wulf, Matthias and Barzanjeh, Shabir and Redchenko, Elena and Rueda Sanchez, Alfredo R and Hease, William J and Hassani, Farid and Fink, Johannes M},
issn = {2041-1723},
journal = {Nature Communications},
keywords = {General Biochemistry, Genetics and Molecular Biology, General Physics and Astronomy, General Chemistry},
publisher = {Springer Nature},
title = {{Converting microwave and telecom photons with a silicon photonic nanomechanical interface}},
doi = {10.1038/s41467-020-18269-z},
volume = {11},
year = {2020},
}
@article{8755,
abstract = {The superconducting circuit community has recently discovered the promising potential of superinductors. These circuit elements have a characteristic impedance exceeding the resistance quantum RQ ≈ 6.45 kΩ which leads to a suppression of ground state charge fluctuations. Applications include the realization of hardware protected qubits for fault tolerant quantum computing, improved coupling to small dipole moment objects and defining a new quantum metrology standard for the ampere. In this work we refute the widespread notion that superinductors can only be implemented based on kinetic inductance, i.e. using disordered superconductors or Josephson junction arrays. We present modeling, fabrication and characterization of 104 planar aluminum coil resonators with a characteristic impedance up to 30.9 kΩ at 5.6 GHz and a capacitance down to ≤ 1 fF, with lowloss and a power handling reaching 108 intra-cavity photons. Geometric superinductors are free of uncontrolled tunneling events and offer high reproducibility, linearity and the ability to couple magnetically - properties that significantly broaden the scope of future quantum circuits. },
author = {Peruzzo, Matilda and Trioni, Andrea and Hassani, Farid and Zemlicka, Martin and Fink, Johannes M},
issn = {23317019},
journal = {Physical Review Applied},
number = {4},
publisher = {American Physical Society},
title = {{Surpassing the resistance quantum with a geometric superinductor}},
doi = {10.1103/PhysRevApplied.14.044055},
volume = {14},
year = {2020},
}
@inproceedings{9001,
abstract = {Quantum illumination is a sensing technique that employs entangled signal-idler beams to improve the detection efficiency of low-reflectivity objects in environments with large thermal noise. The advantage over classical strategies is evident at low signal brightness, a feature which could make the protocol an ideal prototype for non-invasive scanning or low-power short-range radar. Here we experimentally investigate the concept of quantum illumination at microwave frequencies, by generating entangled fields using a Josephson parametric converter which are then amplified to illuminate a room-temperature object at a distance of 1 meter. Starting from experimental data, we simulate the case of perfect idler photon number detection, which results in a quantum advantage compared to the relative classical benchmark. Our results highlight the opportunities and challenges on the way towards a first room-temperature application of microwave quantum circuits.},
author = {Barzanjeh, Shabir and Pirandola, Stefano and Vitali, David and Fink, Johannes M},
booktitle = {IEEE National Radar Conference - Proceedings},
isbn = {9781728189420},
issn = {1097-5659},
location = {Florence, Italy},
number = {9},
publisher = {IEEE},
title = {{Microwave quantum illumination with a digital phase-conjugated receiver}},
doi = {10.1109/RadarConf2043947.2020.9266397},
volume = {2020},
year = {2020},
}
@article{7156,
abstract = {We propose an efficient microwave-photonic modulator as a resource for stationary entangled microwave-optical fields and develop the theory for deterministic entanglement generation and quantum state transfer in multi-resonant electro-optic systems. The device is based on a single crystal whispering gallery mode resonator integrated into a 3D-microwave cavity. The specific design relies on a new combination of thin-film technology and conventional machining that is optimized for the lowest dissipation rates in the microwave, optical, and mechanical domains. We extract important device properties from finite-element simulations and predict continuous variable entanglement generation rates on the order of a Mebit/s for optical pump powers of only a few tens of microwatts. We compare the quantum state transfer fidelities of coherent, squeezed, and non-Gaussian cat states for both teleportation and direct conversion protocols under realistic conditions. Combining the unique capabilities of circuit quantum electrodynamics with the resilience of fiber optic communication could facilitate long-distance solid-state qubit networks, new methods for quantum signal synthesis, quantum key distribution, and quantum enhanced detection, as well as more power-efficient classical sensing and modulation.},
author = {Rueda Sanchez, Alfredo R and Hease, William J and Barzanjeh, Shabir and Fink, Johannes M},
issn = {2056-6387},
journal = {npj Quantum Information},
publisher = {Springer Nature},
title = {{Electro-optic entanglement source for microwave to telecom quantum state transfer}},
doi = {10.1038/s41534-019-0220-5},
volume = {5},
year = {2019},
}
@article{6609,
abstract = {Mechanical systems facilitate the development of a hybrid quantum technology comprising electrical, optical, atomic and acoustic degrees of freedom1, and entanglement is essential to realize quantum-enabled devices. Continuous-variable entangled fields—known as Einstein–Podolsky–Rosen (EPR) states—are spatially separated two-mode squeezed states that can be used for quantum teleportation and quantum communication2. In the optical domain, EPR states are typically generated using nondegenerate optical amplifiers3, and at microwave frequencies Josephson circuits can serve as a nonlinear medium4,5,6. An outstanding goal is to deterministically generate and distribute entangled states with a mechanical oscillator, which requires a carefully arranged balance between excitation, cooling and dissipation in an ultralow noise environment. Here we observe stationary emission of path-entangled microwave radiation from a parametrically driven 30-micrometre-long silicon nanostring oscillator, squeezing the joint field operators of two thermal modes by 3.40 decibels below the vacuum level. The motion of this micromechanical system correlates up to 50 photons per second per hertz, giving rise to a quantum discord that is robust with respect to microwave noise7. Such generalized quantum correlations of separable states are important for quantum-enhanced detection8 and provide direct evidence of the non-classical nature of the mechanical oscillator without directly measuring its state9. This noninvasive measurement scheme allows to infer information about otherwise inaccessible objects, with potential implications for sensing, open-system dynamics and fundamental tests of quantum gravity. In the future, similar on-chip devices could be used to entangle subsystems on very different energy scales, such as microwave and optical photons.},
author = {Barzanjeh, Shabir and Redchenko, Elena and Peruzzo, Matilda and Wulf, Matthias and Lewis, Dylan and Arnold, Georg M and Fink, Johannes M},
journal = {Nature},
pages = {480--483},
publisher = {Nature Publishing Group},
title = {{Stationary entangled radiation from micromechanical motion}},
doi = {10.1038/s41586-019-1320-2},
volume = {570},
year = {2019},
}
@article{436,
abstract = {There has been significant interest recently in using complex quantum systems to create effective nonreciprocal dynamics. Proposals have been put forward for the realization of artificial magnetic fields for photons and phonons; experimental progress is fast making these proposals a reality. Much work has concentrated on the use of such systems for controlling the flow of signals, e.g., to create isolators or directional amplifiers for optical signals. In this Letter, we build on this work but move in a different direction. We develop the theory of and discuss a potential realization for the controllable flow of thermal noise in quantum systems. We demonstrate theoretically that the unidirectional flow of thermal noise is possible within quantum cascaded systems. Viewing an optomechanical platform as a cascaded system we show here that one can ultimately control the direction of the flow of thermal noise. By appropriately engineering the mechanical resonator, which acts as an artificial reservoir, the flow of thermal noise can be constrained to a desired direction, yielding a thermal rectifier. The proposed quantum thermal noise rectifier could potentially be used to develop devices such as a thermal modulator, a thermal router, and a thermal amplifier for nanoelectronic devices and superconducting circuits.},
author = {Barzanjeh, Shabir and Aquilina, Matteo and Xuereb, André},
journal = {Physical Review Letters},
number = {6},
publisher = {American Physical Society},
title = {{Manipulating the flow of thermal noise in quantum devices}},
doi = {10.1103/PhysRevLett.120.060601},
volume = {120},
year = {2018},
}
@article{798,
abstract = {Nonreciprocal circuit elements form an integral part of modern measurement and communication systems. Mathematically they require breaking of time-reversal symmetry, typically achieved using magnetic materials and more recently using the quantum Hall effect, parametric permittivity modulation or Josephson nonlinearities. Here we demonstrate an on-chip magnetic-free circulator based on reservoir-engineered electromechanic interactions. Directional circulation is achieved with controlled phase-sensitive interference of six distinct electro-mechanical signal conversion paths. The presented circulator is compact, its silicon-on-insulator platform is compatible with both superconducting qubits and silicon photonics, and its noise performance is close to the quantum limit. With a high dynamic range, a tunable bandwidth of up to 30 MHz and an in situ reconfigurability as beam splitter or wavelength converter, it could pave the way for superconducting qubit processors with multiplexed on-chip signal processing and readout.},
author = {Barzanjeh, Shabir and Wulf, Matthias and Peruzzo, Matilda and Kalaee, Mahmoud and Dieterle, Paul and Painter, Oskar and Fink, Johannes M},
issn = {20411723},
journal = {Nature Communications},
number = {1},
publisher = {Nature Publishing Group},
title = {{Mechanical on chip microwave circulator}},
doi = {10.1038/s41467-017-01304-x},
volume = {8},
year = {2017},
}