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We have examined both single and entangled two-mode multiphoton coherent states and shown how the `Janus-faced' properties between two partner states are mirrored in appropriate tomograms. Entropic squeezing, quadrature squeezing and…

Quantum Physics · Physics 2018-05-23 Pradip Laha , S Lakshmibala , V Balakrishnan

Quantum phase estimation based on Gaussian states plays a crucial role in many application fields. In this paper, we study the precision bound for the scheme using two-mode squeezed Gaussian states. The quantum Fisher information is…

Quantum Physics · Physics 2024-11-27 Jian-Dong Zhang , Chuang Li , Lili Hou , Shuai Wang

Weak squeezed vacuum light, especially resonant to the atomic transition, plays an important role in quantum storage and generation of various quantum sources. However, the general homodyne detection (HD) cannot determine weak squeezing due…

Quantum Physics · Physics 2021-12-08 Guanhua Zuo , Yuchi Zhang , Jing Li , Shiyao Zhu , Yanqiang Guo , Tiancai Zhang

This review covers recent theoretical and experimental efforts to extend the application of the continuous-variable quantum technology of light beyond "Gaussian" quantum states, such as coherent and squeezed states, into the domain of…

Randomness is a key feature of quantum physics. Heisenberg's uncertainty principle reveals the existence of an intrinsic noise, usually explored through Gaussian squeezed states. Due to their insufficiency for quantum advantage, the focus…

Quantum Physics · Physics 2025-11-20 Vojtěch Kala , Jiří Fadrný , Michal Neset , Jan Bílek , Petr Marek , Miroslav Ježek

A quantum superposition of two coherent states of light with small amplitude can be obtained by subtracting a photon from a squeezed vacuum state. In experiments this preparation can be made conditioned on the detection of a photon in the…

Quantum Physics · Physics 2014-10-09 Anne E. B. Nielsen , Klaus Mølmer

In a new branch of quantum computing, information is encoded into coherent states, the primary carriers of optical communication. To exploit it, quantum bits of these coherent states are needed, but it is notoriously hard to make…

We show that the ground state of the well-known pseudo-stationary states for the Caldirola-Kanai Hamiltonian is a generalized minimum uncertainty state, which has the minimum allowed uncertainty $\Delta q \Delta p = \hbar \sigma_0/2$, where…

Quantum Physics · Physics 2009-11-10 Sang Pyo Kim

Using squeezed states it is possible to surpass the standard quantum limit of measurement uncertainty by reducing the measurement uncertainty of one property at the expense of another complementary property. Squeezed states were first…

Quantum Gases · Physics 2012-03-05 C. D. Hamley , C. S. Gerving , T. M. Hoang , E. M. Bookjans , M. S. Chapman

It is important to find feasible measurement bounds for quantum information protocols. We present analytic bounds for quantum illumination with Gaussian states when using an on-off detection or a photon number resolving (PNR) detection,…

Quantum Physics · Physics 2023-11-06 Su-Yong Lee , Dong Hwan Kim , Yonggi Jo , Taek Jeong , Duk Y. Kim , Zaeill Kim

Squeezed states of light are one of the most important fundamental resources for quantum optics, optical quantum information processing and quantum sensing. Recently, it has been experimentally demonstrated that the squeezing of single-mode…

Quantum Physics · Physics 2025-08-26 Jaromír Fiurášek , Stephan Grebien , Roman Schnabel

Photon number-squeezed states are of significant value in fundamental quantum research and have a wide range of applications in quantum metrology. Most of their preparation mechanisms require precise control of quantum dynamics and are less…

Quantum Physics · Physics 2023-08-25 Baiqiang Zhu , Keye Zhang , Weiping Zhang

We address local quantum estimation of bilinear Hamiltonians probed by Gaussian states. We evaluate the relevant quantum Fisher information (QFI) and derive the ultimate bound on precision. Upon maximizing the QFI we found that single- and…

Quantum Physics · Physics 2009-11-13 Roberto Gaiba , Matteo G A Paris

We have created heralded coherent state superpositions (CSS), by subtracting up to three photons from a pulse of squeezed vacuum light. To produce such CSSs at a sufficient rate, we used our high-efficiency photon-number-resolving…

Quantum technologies, encompassing communication, computation, and metrology, rely on the generation and control of non-Gaussian states of light. These states enable secure quantum communication, fault-tolerant quantum computation, and…

Quantum Physics · Physics 2025-12-03 Ozlem Erkilic , Aritra Das , Biveen Shajilal , Ping Koy Lam , Timothy C. Ralph , Syed M. Assad

We discuss nonclassical properties of single-photon subtracted squeezed vacuum states in terms of the sub-Poissonian statistics and the negativity of the Wigner function. We derive a compact expression for the Wigner function from which we…

Quantum Physics · Physics 2016-08-08 Asoka Biswas , G. S. Agarwal

A "squeezed-vacuum" state considered in quantum optics is shown to be realized in the ground-state wavefunction for the bilayer quantum Hall system at the total Landau level filling of $\nu=1/m$ (m: odd integer). This is derived in the…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 T. Nakajima , H. Aoki

The widespread availability of quantum entanglement with photons, in the guise of two-mode squeezed states, can be attributed to the phenomenon of parametric down-conversion. A reinterpretation of this effect with macroscopic mechanical…

Mesoscale and Nanoscale Physics · Physics 2014-10-21 I. Mahboob , H. Okamoto , K. Onomitsu , H. Yamaguchi

According to quantum theory the interactions between physical systems are quantized. As a direct consequence, measurement sensitivities are fundamentally limited by quantization noise, or just `quantum noise' in short. Furthermore,…

Quantum Physics · Physics 2017-12-19 Roman Schnabel

Quantum coherence is one of the clearest departures from classical physics, exhibited when a system is in a superposition of different basis states. Here the coherent superposition of three motional Fock states of a single trapped ion is…