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The observation of quantum phenomena often necessitates sufficiently pure states, a requirement that can be challenging to achieve. In this study, our goal is to prepare a non-classical state originating from a mixed state, utilizing…

Quantum Physics · Physics 2025-04-08 Ian Yang , Thomas Agrenius , Vasilisa Usova , Oriol Romero-Isart , Gerhard Kirchmair

State representations summarize our knowledge about a system. When unobservable quantities are introduced the state representation is typically no longer unique. However, this non-uniqueness does not affect subsequent inferences based on…

Quantum Physics · Physics 2009-11-10 Kae Nemoto , Samuel L. Braunstein

The negativity of a given state's Wigner function has been proposed as a measure of quantumness of that state in a unipartite system. This otherwise physically intuitive and useful phase-space measure however does not yield the right…

Quantum Physics · Physics 2008-11-19 Tyler E Keating , Adam T. C. Steege , Arjendu K. Pattanayak

We study the possibility to create many-particle Schr\"odinger cat-like states by using a Feshbach resonance to reverse the sign of the scattering length of a Bose-Einstein condensate trapped in a double-well potential. To address the issue…

Other Condensed Matter · Physics 2007-05-23 Y. P. Huang , M. G. Moore

Quantum non-Gaussian states are crucial for the fundamental understanding of non-linear bosonic systems and simultaneously advanced applications in quantum technologies. In many bosonic experiments the important quantum non-Gaussian feature…

Quantum Physics · Physics 2025-10-07 Jan Provazník , Petr Marek , Julien Laurat , Radim Filip

Decoherence is the process via which quantum superpositions states are reduced to classical mixtures. Decoherence has been predicted for relativistically accelerated quantum systems, however examples to date have involved restricting the…

Quantum Physics · Physics 2019-01-16 Daiqin Su , Timothy C. Ralph

Using tomographic reconstruction we determine the complete internuclear quantum state, represented by the Wigner function, of a dissociating I2 molecule based on femtosecond time resolved position and momentum distributions of the atomic…

Quantum Physics · Physics 2009-11-10 Esben Skovsen , Henrik Stapelfeldt , Soren Juhl , Klaus Molmer

This is a brief description of how to protect quantum states from dissipation and decoherence that arise due to uncontrolled interactions with the environment. We discuss recoherence and stabilisation of quantum states based on two…

Quantum Physics · Physics 2007-05-23 A. Ekert , C. Macchiavello

It is commonly stated that decoherence in open quantum systems is due to growing entanglement with an environment. In practice, however, surprisingly often decoherence may equally well be described by random unitary dynamics without…

Quantum Physics · Physics 2009-10-29 Julius Helm , Walter T. Strunz

We found that in contrast with the common premise, a measurement on the environment of an open quantum system can {\em reduce} its decoherence rate. We demonstrate it by studying an example of indirect qubit's measurement, where the…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Yin Ye , Yunshan Cao , Xin-Qi Li , Shmuel Gurvitz

It has been recently proved that a quantum jump may be reversed by a unitary process provided the initial state is restricted by some conditions. The application of such processes for preventing decoherence, for example in quantum…

Quantum Physics · Physics 2009-11-06 Michael B. Mensky

We demonstrate a state reconstruction technique which provides either the Wigner function or the density matrix of a field mode and requires only avalanche photodetectors, without any phase or amplitude discrimination power. It represents…

We show how to optimally protect quantum states and quantum entanglement under non-zero temperature based on measurement reversal from weak measurement. In particular, we present explicit formulas of the protection.

Quantum Physics · Physics 2014-02-19 S. C. Wang , Z. W. Yu , X. B. Wang

We derive sampling functions for estimation of quantum state fidelity with Schr\"odinger cat-like states, which are defined as superpositions of two coherent states with opposite amplitudes. We also provide sampling functions for fidelity…

Quantum Physics · Physics 2015-06-16 Jaromir Fiurasek , Miroslav Jezek

We study the dynamics of quantum coherence under Unruh thermal noise and seek under which condition the coherence can be frozen in a relativistic setting. We find that the frozen condition is either (i) the initial state is prepared as a…

Quantum Physics · Physics 2016-06-08 Jieci Wang , Zehua Tian , Jiliang Jing , Heng Fan

Certain quantum states are well-known to be particularly fragile in the presence of decoherence, as illustrated by Schrodinger's famous gedanken cat experiment. It has been better appreciated more recently that quantum states can be…

Physical systems usually exhibit quantum behavior, such as superpositions and entanglement, only when they are sufficiently decoupled from a lossy environment. Paradoxically, a specially engineered interaction with the environment can…

Quantum decoherence is seen as an undesired source of irreversibility that destroys quantum resources. Quantum coherences seem to be a property that vanishes at thermodynamic equilibrium. Away from equilibrium, quantum coherences challenge…

Quantum Physics · Physics 2013-08-13 César A. Rodríguez-Rosario , Thomas Frauenheim , Alán Aspuru-Guzik

Due to the interaction with the environment, a quantum state is subjected to decoherence which becomes one of the biggest problems for practical quantum computation. Amplitude damping is one of the most important decoherence processes.…

Quantum Physics · Physics 2016-08-03 Saeideh Shahrokh Esfahani , Zeyang Liao , M. Suhail Zubairy

The decoherence induced on a single qubit by its interaction with the environment is studied. The environment is modelled as a scalar two-level boson system that can go through either first order or continuous excited state quantum phase…

Quantum Physics · Physics 2015-05-14 P. Perez-Fernandez , A. Relano , J. M. Arias , J. Dukelsky , J. E. Garcia-Ramos