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Coherent superposition states of a mesoscopic quantum object play a major role in our understanding of the quantum to classical boundary, as well as in quantum-enhanced metrology and computing. However, their practical realization and…

At absolute zero temperature, thermal noise vanishes when a physical system is in its ground state, but quantum noise remains as a fundamental limit to the accuracy of experimental measurements. Such a limitation, however, can be mitigated…

Condensed Matter · Physics 2009-11-10 J. Zhao , A. V. Bragas , D. J. Lockwood , R. Merlin

Quantisation with Gaussian type states offers certain advantages over other quantisation schemes, in particular, they can serve to regularise formally discontinuous classical functions leading to well defined quantum operators. In this work…

Quantum Physics · Physics 2022-05-25 Jean-Pierre Gazeau , Véronique Hussin , James Moran , Kevin Zelaya

Quantum-optical research on semiconductor single-photon sources puts special emphasis on the measurement of the second-order correlation function $g^{(2)}(\tau)$, arguing that $g^{(2)}(0)<1/2$ implies the source field represents a good…

Quantum Physics · Physics 2019-09-13 Peter Grünwald

It is well known that the Helstrom bound can be improved by generalizing the form of a coherent state. Thus, designing a quantum measurement achieving the improved Helstrom bound is important for novel quantum communication. In the present…

Quantum Physics · Physics 2022-03-30 Min Namkung , Jeong San Kim

In recent years, there has been an increased interest in the generation of superposition of coherent states with opposite phases, the so-called photonic Schrodinger-cat states. These experiments are very challenging and so far, cats…

Quantum Physics · Physics 2015-10-28 E. Oudot , P. Sekatski , F. Fröwis , N. Gisin , N. Sangouard

The pair coherent state (PCS) is a theoretical extension of the Glauber coherent state to two harmonic oscillators. It is an interesting class of non-Gaussian continuous-variable entangled state and is also at the heart of a promising…

Quantum Physics · Physics 2022-09-26 Jeffrey M. Gertler , Sean van Geldern , Shruti Shirol , Liang Jiang , Chen Wang

Loss measurements are at the base of spectroscopy and imaging, thus perme- ating all the branches of science, from chemistry and biology to physics and material science. However, quantum mechanics laws set the ultimate limit to the…

Quantum Physics · Physics 2018-05-17 Elena Losero , Ivano Ruo-Berchera , Alice Meda , Alessio Avella , Marco Genovese

We introduce an encoding of information in the relative displacement or photon number of different optical modes. Since the loss rate to interference is insensitive to squeezing and many non-Gaussian fluctuations, such a space is relatively…

Quantum Physics · Physics 2026-04-03 Uchenna Chukwu , Mohammad-Ali Miri , Nicholas Chancellor

Identification, and subsequent quantification of quantum correlations, is critical for understanding, controlling, and engineering quantum devices and processes. We derive and implement a general method to quantify various forms of quantum…

Quantum Physics · Physics 2023-02-09 Artur Barasinski , Jan Perina , Antonin Cernoch

The dynamics of the Jaynes-Cummings interaction of a two-level atom interacting with a single mode of the radiation field is investigated, as the state of the field is gradually changed from a coherent state to a squeezed coherent state.…

Quantum Physics · Physics 2012-03-22 T. Subeesh , Vivishek Sudhir , A. B. M. Ahmed , M. Venkata Satyanarayana

A theory of quantum state reduction is advanced. It is based on two principles: (1) Gauge decomposition; (2) Maximum entropy. To wit: (1) The reduction decomposition of a state vector is the Schmidt decomposition with respect to the states…

Quantum Physics · Physics 2009-01-05 Vladimir S. Mashkevich

One of the most fundamental quantum states of light is squeezed vacuum, in which noise in one of the quadratures is less than the standard quantum noise limit. Significant progress has been made in the generation of optical squeezed vacuum…

Quantum Physics · Physics 2022-10-05 Rajveer Nehra , Ryoto Sekine , Luis Ledezma , Qiushi Guo , Robert M. Gray , Arkadev Roy , Alireza Marandi

Quantum state discrimination plays a central role in quantum information and communication. For the discrimination of optical quantum states, the two most widely adopted measurement techniques are photon detection, which produces discrete…

Quantum Physics · Physics 2026-03-11 James Moran , Spiros Kechrimparis , Hyukjoon Kwon

We present a systematic Magnus expansion treatment of light-matter interaction beyond the Rotating Wave Approximation. We show that at the second order of Magnus series, the time-evolution operator acquires both energy-shifts and squeezing…

Quantum Physics · Physics 2026-02-02 Phoenix M. M. Paing , Daniel F. V. James

The use of special quantum states to achieve sensitivities below the limits established by classically behaving states has enjoyed immense success since its inception. In bosonic interferometers, squeezed states, number states and cat…

In this work, we introduce a non-Gaussian quantum state named excited squeezed vacuum state (ESVS), which can be ustilized to describe quantum light field emitted from the multiphoton quantum process occurred in some restricted quantum…

Quantum Physics · Physics 2015-06-23 Xubing Tang , Fang Gao , Yaoxiong Wan , Jianguang Wu , Feng Shuang

Bosonic two-mode squeezed states are paradigmatic entangled states with broad applications in quantum information processing and quantum metrology. In this work, we propose a two-mode squeezing scheme in a hybrid three-mode cavity…

Quantum Physics · Physics 2026-01-21 Chen Wang , Shi-fan Qi

Fast and precise characterization of Gaussian states is crucial for their effective use in quantum technologies. In this work, we apply a multi-parameter moment-based estimation method that enables rapid and accurate determination of…

Quantum coherence is the basic concept of superposition of quantum states and plays an important role in quantum metrology. We show how a pair of uniformly accelerated observers with a local two-mode Gaussian quantum state affects the…

Quantum Physics · Physics 2023-04-18 Xiaolong Gong , Yue Fang , Tonghua Liu , Shuo Cao