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Repeated observations of inhomogeneity in cuperate superconductors[1-5] make one immediately question the existance of coherent quasiparticles(qp's) and the applicability of a momentum space picture. Yet, obversations of interference…

Superconductivity · Physics 2010-04-13 Eun-Ah Kim , Michael J. Lawler

Observing quantum effects such as superpositions and entanglement in macroscopic systems requires not only a system that is well protected against environmental decoherence, but also sufficient measurement precision. Motivated by recent…

Quantum Physics · Physics 2012-02-21 Sadegh Raeisi , Pavel Sekatski , Christoph Simon

Construction of an optical quantum computer (OQC) is finished by implementing all necessary ingredients with light (photon). There is, however, one more hurdle to clear. It is scalability, which is easily lost when accommodating many qubits…

Quantum Physics · Physics 2010-09-28 T. Asaba , S. Fukatsu

Complexity in strongly correlated electron systems is analyzed by considering decoherence process between the localized state, |L> and the itinerant state, |I>. The coherent superposition state of a|I> + b|L> decoheres to the pointer states…

Strongly Correlated Electrons · Physics 2011-01-04 Byung Gyu Chae

Quantum measurements have intrinsic properties which seem incompatible with our everyday-life macroscopic measurements. Macroscopic Quantum Measurement (MQM) is a concept that aims at bridging the gap between well understood microscopic…

Quantum Physics · Physics 2018-01-17 Marc-Olivier Renou , Nicolas Gisin , Florian Fröwis

Harnessing entanglement and quantum coherence plays a central role in advancing quantum technologies. In quantum optical light-atom platforms, these two fundamental resources are often associated with a Jaynes-Cummings model description…

Quantum Physics · Physics 2024-09-25 Pradip Laha , P. A. Ameen Yasir , Peter van Loock

A model is presented to describe the recently proposed experiment (J. Raimond, M. Brune and S. Haroche Phys. Rev. Lett {\bf 79}, 1964 (1997)) where a mesoscopic superposition of radiation states is prepared in a high-Q cavity which is…

Quantum Physics · Physics 2016-09-08 S. G. Mokarzel , A. N. Salgueiro , M. C. Nemes

A scheme for optimal Gaussian cloning of optical coherent states is proposed and experimentally demonstrated. Its optical realization is based entirely on simple linear optical elements and homodyne detection. The optimality of the…

Quantum Physics · Physics 2009-11-11 Ulrik L. Andersen , Vincent Josse , Gerd Leuchs

We discuss several methods to produce superpositions of optical coherent states (also known as "cat states"). Cat states have remarkable properties that could allow them to be powerful tools for quantum information processing and metrology.…

Quantum Physics · Physics 2009-11-13 S. Glancy , H. M. Vasconcelos

Macroscopic quantum superpositions are widely believed to be unobservable because large systems cannot be perfectly isolated from their environments. Here, we show that even under perfect isolation, intrinsic unitary dynamics with the…

Quantum Physics · Physics 2025-12-15 Gabriel Dias Carvalho , Pedro S. Correia , Thiago R. de Oliveira

The well studied quantum optical Schr\"{o}dinger cat state is a superposition of two distinguishable states, with quantum coherence between these macroscopically distinguishable states being of foundational and, in the context of…

Quantum Physics · Physics 2019-06-12 Namrata Shukla , Naeem Akhtar , Barry C. Sanders

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 identify a class of quantum states, each consisting of a microscopic and a macroscopic section, that are effectively decoherence-free when each particle is locally passed through a quantum channel. In particular, and in contrast to other…

Quantum Physics · Physics 2014-12-31 Utkarsh Mishra , Aditi Sen De , Ujjwal Sen

A quantum cloning machine is introduced that yields $M$ identical optimal clones from $N$ replicas of a coherent state and $N'$ replicas of its phase conjugate. It also optimally produces $M'=M+N'-N$ phase-conjugated clones at no cost. For…

Quantum Physics · Physics 2009-11-07 N. J. Cerf , S. Iblisdir

The cloning of continuous quantum variables is analyzed based on the concept of Gaussian cloning machines, i.e., transformations that yield copies that are Gaussian mixtures centered on the state to be copied. The optimality of Gaussian…

Quantum Physics · Physics 2009-11-06 N. J. Cerf , S. Iblisdir

Superposition is one of the most distinct features of quantum theory and has been demonstrated in numerous realizations of Young's classical double-slit interference experiment and its analogues. However, quantum entanglement - a…

Quantum information science is driving progress in a vast number of scientific and technological areas that cover molecular spectroscopy and matter-light interactions in general. In these fields, the ability to generate quantum…

Quantum Physics · Physics 2023-03-02 M Wittkop , Juan M. Marmolejo-Tejada , Martín A. Mosquera

We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate…

Quantum Physics · Physics 2007-05-23 A. Serafini , M. G. A. Paris , F. Illuminati , S. De Siena

In [7] the authors of this paper argued in favor of the possibility to consider a Paraconsistent Approach to Quantum Superpositions (PAQS). We claimed that, even though most interpretations of quantum mechanics (QM) attempt to escape…

Quantum Physics · Physics 2015-07-13 Newton da Costa , Christian de Ronde

The properties of coherence and polarization of light has been the subject of intense investigations and form the basis of many technological applications. These concepts which historically have been treated independently can now be…

Quantum Physics · Physics 2021-01-07 Bertúlio de Lima Bernardo