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We demonstrate an angular momentum-enhanced protocol that permits an angular displacement estimation by using tunable squeezed Bell state and parity detection. We consider the resolution and the sensitivity, super-resolution is presented…

Quantum Physics · Physics 2019-02-25 Jian-Dong Zhang , Zi-Jing Zhang , Long-Zhu Cen , Yuan Zhao

Applying the recently developed formalism of quantum-state transformation at absorbing dielectric four-port devices [L.~Kn\"oll, S.~Scheel, E.~Schmidt, D.-G.~Welsch, and A.V.~Chizhov, Phys. Rev. A {\bf 59}, 4716 (1999)], we calculate the…

Quantum Physics · Physics 2009-11-06 Stefan Scheel , Tomas Opatrny , Dirk-Gunnar Welsch

We show how high fidelity quantum teleportation of light to atoms can be achieved in the same setup as was used in the recent experiment [J. Sherson et.al., quant-ph/0605095, accepted by Nature], where such an inter-species quantum state…

Quantum Physics · Physics 2007-05-23 K. Hammerer , E. S. Polzik , J. I. Cirac

Tracking a randomly varying optical phase is a key task in metrology, with applications in optical communication. The best precision for optical phase tracking has till now been limited by the quantum vacuum fluctuations of coherent light.…

We investigate the separability, nonlocality and squeezing of continuous-variable analogue of the Werner state: a mixture of pure two-mode squeezed vacuum state with local thermal radiations. Utilizing this Werner state, coherent-state…

Quantum Physics · Physics 2016-09-08 Ladislav Mista , Radim Filip , Jaromir Fiurasek

We address continuous variable quantum teleportation in Gaussian quantum noisy channels, either thermal or squeezed-thermal. We first study the propagation of twin-beam and evaluate a threshold for its separability. We find that the…

Quantum Physics · Physics 2015-06-26 Stefano Olivares , Matteo G. A. Paris , Andrea R. Rossi

Entanglement is a key quantum feature that enables quantum sensors to improve their sensitivity up to the Heisenberg limit. In the NV center platform, the Heisenberg limit can only be achieved when the axes of the NV centers are parallel.…

Quantum Physics · Physics 2025-07-28 Marcel Morillas-Rozas , Alberto López-García , Javier Cerrillo

We show, by making conditional measurements on the Einstein-Podolsky-Rosen (EPR) squeezed vacuum, that one can improve the efficacy of teleportation for both the position difference, momentum sum and number difference, phase sum continuous…

Quantum Physics · Physics 2007-05-23 P. T. Cochrane , T. C. Ralph , G. J. Milburn

Teleportation is a basic primitive for quantum communication and quantum computing. We address the problem of continuous-variable (unconditional and conditional) teleportation of a pure single-photon state and a mixed attenuated…

Quantum Physics · Physics 2015-05-20 Ladislav Mišta, , Radim Filip , Akira Furusawa

Transferring quantum information between different types of quantum hardware is crucial for integrated quantum technology. In particular, converting information between continuous-variable (CV) and discrete-variable (DV) devices enables…

Quantum Physics · Physics 2024-03-25 Alexandru Macridin , Andy C. Y. Li , Panagiotis Spentzouris

We propose here a new idea for quantum teleportation of superposed coherent state which is not only almost perfect, in principle, but also feasible experimentally. We use entangled resource $\sim…

Quantum Physics · Physics 2020-10-15 Ravi Kamal Pandey , Ranjana Prakash , Hari Prakash

Quantum-enhanced phase estimation paves the way to ultra-precision sensing and is of great realistic significance. In this paper we investigate theoretically the estimation of a second-order nonlinear phase shift using a coherent state and…

Quantum Physics · Physics 2019-02-13 Jian-Dong Zhang , Zi-Jing Zhang , Long-Zhu Cen , Jun-Yan Hu , Yuan Zhao

Continuous-variable quantum key distribution (CV QKD) using optical coherent detectors is practically favorable due to its low implementation cost, flexibility of wavelength division multiplexing, and compatibility with standard coherent…

Quantum Physics · Physics 2025-08-05 Anran Jin , Xingjian Zhang , Liang Jiang , Richard V. Penty , Pei Zeng

Robust quantum state transfer (QST) is an indispensable ingredient in scalable quantum information processing. Here we present an experimentally feasible mechanism for realizing robust QST via topologically protected edge states in…

Quantum Physics · Physics 2019-01-11 Feng Mei , Gang Chen , Lin Tian , Shi-Liang Zhu , Suotang Jia

Quantum state tomography is an essential component of modern quantum technology. In application to continuous-variable harmonic-oscilator systems, such as the electromagnetic field, existing tomography methods typically reconstruct the…

Quantum Physics · Physics 2023-01-09 Ekaterina Fedotova , Nikolai Kuznetsov , Egor Tiunov , A. E. Ulanov , A. I. Lvovsky

The canonical Mach-Zehnder interferometer fed with a coherent state and a squeezed-vacuum state of equal intensities is theoretically predicted to achieve Heisenberg scaling in phase sensitivity. However, this ultimate performance is…

Quantum Physics · Physics 2026-05-04 Yi Gu , Song-Ping Wang , Wei Zhong

The recent launch of the Micius quantum-enabled satellite heralds a major step forward for long-range quantum communication. Using single-photon discrete-variable quantum states, this exciting new development proves beyond any doubt that…

Quantum Physics · Physics 2019-08-08 Nedasadat Hosseinidehaj , Robert Malaney , Soon Xin Ng , Lajos Hanzo

We investigate the role of quadrature squeezing in the quantum teleportation protocol for coherent states, using non-Gaussian resource states. For the two-mode systems, the non-Gaussian resource states that we use are obtained by an…

Quantum Physics · Physics 2025-02-25 Mohak Sharma , Chandan Kumar , Shikhar Arora , Arvind

We propose a method to refine entanglement via swapping from a pair of squeezed vacuum states by performing the Bell measurement of number sum and phase difference. The resultant states are maximally entangled by adjusting the two squeezing…

Quantum Physics · Physics 2009-11-07 Akira Kitagawa , Katsuji Yamamoto

Quantum teleportation, a way to transfer the state of a quantum system from one location to another, is central to quantum communication and plays an important role in a number of quantum computation protocols. Previous experimental…