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We propose a scheme for generating the Schr\"{o}dinger cat state based on geometric operations by a nanomechanical resonator coupled to a superconducting charge qubit. The charge qubit, driven by two strong classical fields, interacts with…

Mesoscale and Nanoscale Physics · Physics 2015-01-14 Jian-Qi Zhang , Wei Xiong , Shuo Zhang , Yong Li , Mang Feng

Circuit quantum electrodynamics ('circuit QED') describes the quantum mechanics and quantum field theory of superconducting electrical circuits operating in the microwave regime near absolute zero temperature. It is the analog of cavity QED…

Quantum Physics · Physics 2017-10-10 S. M. Girvin

In this paper, we are interested in detecting the presence of a nearby phase-sensitive object, where traveling light works out under a low-photon loss rate. Here we investigate the optimal quantum phase estimation with generalized…

Quantum Physics · Physics 2020-07-30 Seung-Woo Lee , Su-Yong Lee , Jaewan Kim

We outline a toolbox comprised of passive optical elements, single photon detection and superpositions of coherent states (Schrodinger cat states). Such a toolbox is a powerful collection of primitives for quantum information processing…

Quantum Physics · Physics 2009-11-10 A. Gilchrist , Kae Nemoto , W. J. Munro , T. C. Ralph , S. Glancy , Samuel. L. Braunstein , G. J. Milburn

We examine heralded nondeterministic noiseless amplification based on the quantum scissors device, which has been shown to increase the one-photon amplitude of a state at the expense of the vacuum-state amplitude. Here we propose using the…

Quantum Physics · Physics 2015-03-17 John Jeffers

Macroscopic quantum superpositions, such as mechanical Schr\"odinger cat states, are central to emerging quantum technologies in sensing and bosonic error-correcting codes. We propose a scheme to generate such states by coupling a…

Quantum Physics · Physics 2026-01-26 M. Tahir Naseem

Photonics offers unique advantages as a substrate for quantum information processing, but imposes fundamental scalability challenges. Nondeterministic schemes impose massive resource overheads, while deterministic schemes require…

Quantum Physics · Physics 2021-12-02 Ben Bartlett , Avik Dutt , Shanhui Fan

The iconic Schr\"odinger's cat state describes a system that may be in a superposition of two macroscopically distinct states, for example two clearly separated oscillator coherent states. Quite apart from their role in understanding the…

Quantum Physics · Physics 2014-12-25 M. J. Everitt , T. P. Spiller , G. J. Milburn , R. D. Wilson , A. M. Zagoskin

We demonstrate an optical method to engineer optical Schr\"odinger cat states (SCSs) of large size beta ranging from beta=2 to beta=3 with high fidelity close to 0.99. Our approach uses the alpha-representation of the SCSs in infinite…

Quantum Physics · Physics 2019-06-14 Evgeny V. Mikheev , Sergey A. Podoshvedov , Nguyen Ba An

High-dimensional quantum systems are a valuable resource for quantum information processing. They can be used to encode error-correctable logical qubits, which has been demonstrated using continuous-variable states in microwave cavities or…

The Dicke-Ising model, one of the few paradigmatic models of matter-light interaction, exhibits a superradiant quantum phase transition above a critical coupling strength. However, in natural optical systems, its experimental validation is…

Quantum Physics · Physics 2025-10-16 Dmitriy S. Shapiro , Yannik Weber , Tim Bode , Frank K. Wilhelm , Dmitry Bagrets

Schr\"odinger cat states, which are superpositions of macroscopically distinct states, are potentially critical resources for upcoming quantum information technologies. In this paper, we introduce a scheme to generate entangled…

High Energy Physics - Theory · Physics 2024-08-14 Partha Nandi , Nandita Debnath , Subhajit Kala , A. S. Majumdar

We show how macroscopically distinct quantum superposition states (Schroedinger cat states) may be used as logical qubit encodings for the correction of spontaneous emission errors. Spontaneous emission causes a bit flip error which is…

Quantum Physics · Physics 2009-10-31 P. T. Cochrane , G. J. Milburn , W. J. Munro

Optical Schrodinger's cat (SC) is highly anticipated because of the potential of realizing fault-tolerant quantum computing, but the practical merit is only shown when the amplitude is larger than 2. However, such high-amplitude cats have…

Quantum Physics · Physics 2024-07-04 Nuo Wang , Xinchen Zhang , Qi Liu , Fengxiao Sun , Qiongyi He , Ying Gu

It is a fundamental principle of quantum theory that an unknown state cannot be copied or, as a consequence, an unknown optical signal cannot be amplified deterministically and perfectly. Here we describe a protocol that provides…

Quantum Physics · Physics 2013-11-25 Electra Eleftheriadou , Stephen M. Barnett , John Jeffers

We present a comprehensive study of the transient dynamics of multimode Schr\"odinger cat states in dissipatively coupled resonator arrays using the positive-P phase-space method. By employing the positive-P representation, we derive the…

Quantum Physics · Physics 2026-01-13 Yi Shi , Alex Ferrier , Piotr Deuar , Eran Ginossar , Marzena Szymanska

Optical coherent states are classical light fields with high purity, and are essential carriers of information in optical networks. If these states could be controlled in the quantum regime, allowing for their quantum superposition…

Quantum Physics · Physics 2013-11-13 Jonas S. Neergaard-Nielsen , Yujiro Eto , Chang-Woo Lee , Hyunseok Jeong , Masahide Sasaki

We propose a scheme to generate spin cat states, i.e., superpositions of maximally separated quasiclassical states on a single high-dimensional nuclear spin in a solid-state device. We exploit a strong quadrupolar nonlinearity to drive the…

Quantum Physics · Physics 2024-01-30 Pragati Gupta , Arjen Vaartjes , Xi Yu , Andrea Morello , Barry C. Sanders

We propose novel coherent-state phase concentration by probabilistic measurement-induced ampli- fication. The amplification scheme uses novel architecture, thermal noise addition (instead of single photon addition) followed by feasible…

Quantum Physics · Physics 2015-05-13 Petr Marek , Radim Filip

Coherent manipulation of an increasing number of qubits for the generation of entangled states has been an important goal and benchmark in the emerging field of quantum information science. The multiparticle entangled states serve as…