scholarly journals Quantum Rayleigh Annihilation of Entangled Photons

2018 ◽  
Author(s):  
Andre Vatarescu
Keyword(s):  
Physical Reality ◽  
Quantum States ◽  
Entangled States ◽  
Entangled Photons ◽  
Dielectric Media ◽  
Quantum Phenomenon ◽  
Quantum Non Locality ◽  
Linearly Polarized ◽  
Photonic States ◽  
Non Locality

The interpretation of published experimental results intended to prove the existence of a quantum phenomenon of non-locality involving photonic entangled states did not take into consideration the existence of the quantum Rayleigh conversion of photons in dielectric media. This phenomenon leads to the existence of high levels of correlations between two independent photonic and linearly polarized quantum states generated after the entangled photons have been absorbed through the quantum Rayleigh conversion. Both pure and mixed individual states of polarization result in expressions normally associated with entangled photonic states, providing support for the view that the physical reality of quantum non-locality is highly questionable.

scholarly journals Quantum Rayleigh Annihilation of Entangled Photons

2018 ◽  
Author(s):  
Andre Vatarescu
Keyword(s):  
Physical Reality ◽  
Quantum States ◽  
Entangled States ◽  
Entangled Photons ◽  
Dielectric Media ◽  
Quantum Phenomenon ◽  
Quantum Non Locality ◽  
Linearly Polarized ◽  
Photonic States ◽  
Non Locality

The interpretation of published experimental results intended to prove the existence of a quantum phenomenon of non-locality involving photonic entangled states did not take into consideration the existence of the quantum Rayleigh conversion of photons in dielectric media. This phenomenon leads to the existence of high levels of correlations between two independent photonic and linearly polarized quantum states generated after the entangled photons have been absorbed through the quantum Rayleigh conversion. Both pure and mixed individual states of polarization result in expressions normally associated with entangled photonic states, providing support for the view that the physical reality of quantum non-locality is highly questionable.

“Non-locality”

2017 ◽  
Author(s):  
Richard Healey
Keyword(s):  
Quantum Theory ◽  
Quantum Entanglement ◽  
Quantum States ◽  
Entangled States ◽  
Entangled Quantum States ◽  
Action At A Distance ◽  
Insight Into ◽  
Non Locality

Quantum entanglement is popularly believed to give rise to spooky action at a distance of a kind that Einstein decisively rejected. Indeed, important recent experiments on systems assigned entangled states have been claimed to refute Einstein by exhibiting such spooky action. After reviewing two considerations in favor of this view I argue that quantum theory can be used to explain puzzling correlations correctly predicted by assignment of entangled quantum states with no such instantaneous action at a distance. We owe both considerations in favor of the view to arguments of John Bell. I present simplified forms of these arguments as well as a game that provides insight into the situation. The argument I give in response turns on a prescriptive view of quantum states that differs both from Dirac’s (as stated in Chapter 2) and Einstein’s.

scholarly journals Topologically protected entangled photonic states

Nanophotonics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 1327-1335 ◽  
Author(s):  
Michelle Wang ◽  
Cooper Doyle ◽  
Bryn Bell ◽  
Matthew J. Collins ◽  
Eric Magi ◽  
...  
Keyword(s):  
Quantum Information ◽  
Disordered Systems ◽  
Quantum States ◽  
Entangled States ◽  
Single Photons ◽  
Noise Sources ◽  
Topological Structures ◽  
Fabrication Defects ◽  
Photonic States

AbstractEntangled multiphoton states lie at the heart of quantum information, computing, and communications. In recent years, topology has risen as a new avenue to robustly transport quantum states in the presence of fabrication defects, disorder, and other noise sources. Whereas topological protection of single photons and correlated photons has been recently demonstrated experimentally, the observation of topologically protected entangled states has thus far remained elusive. Here, we experimentally demonstrate the topological protection of spatially entangled biphoton states. We observe robustness in crucial features of the topological biphoton correlation map in the presence of deliberately introduced disorder in the silicon nanophotonic structure, in contrast with the lack of robustness in non-topological structures. The topological protection is shown to ensure the coherent propagation of the entangled topological modes, which may lead to robust propagation of quantum information in disordered systems.

Entanglement

Quantum 20/20 ◽  
2019 ◽  
pp. 151-162
Author(s):  
Ian R. Kenyon
Keyword(s):  
Quantum States ◽  
Entangled States ◽  
Entangled State ◽  
Entangled Photons ◽  
Photon State ◽  
Full Knowledge ◽  
Quantum Entangled States ◽  
The Individual ◽  
Down Conversion ◽  
Individual Particles

The distiction between classical product states and quantum entangled states is disclosed with examples. Spontaneous parametric down conversion as a source of entangled photons is described. The action of a perfect beam splitter is analysed using creation and annihilation operators. The HOM interferometer is described. Its use in demonstrating the indistinguishability of photons and in measuring bandwidth of sources at the level of femtoseconds is recounted. Two particle entanglement is analysed using the Bloch sphere representation showing how the full knowledge of the entangled state does not fix the state of the individual particles. The four Bell states, eigenstates of two particle entanglement, are introduced. Teleportation of a photon state using entangled photons is described, and an experiment to entangle the quantum states of atoms at space-like separation outlined.

An anomaly of non-locality

2007 ◽  
Vol 7 (1&2) ◽  
pp. 157-170 ◽  
Author(s):  
A.A. Methot ◽  
V. Scarani
Keyword(s):  
Bell Inequalities ◽  
Present Knowledge ◽  
Quantum States ◽  
Entangled States ◽  
Low Dimensions ◽  
Local Correlations ◽  
Non Local ◽  
Entangled Quantum States ◽  
Maximally Entangled States ◽  
Non Locality

Ever since the work of Bell, it has been known that entangled quantum states can produce non-local correlations between the outcomes of separate measurements. However, for almost forty years, it has been assumed that the most non-local states would be the maximally entangled ones. Surprisingly it is not the case: non-maximally entangled states are generally more non-local than maximally entangled states for all the measures of non-locality proposed to date: Bell inequalities, the Kullback-Leibler distance, entanglement simulation with communication or with non-local boxes, the detection loophole and efficiency of cryptography. In fact, one can even find simple examples in low dimensions, confirming that it is not an artefact of a specifically constructed Hilbert space or topology. This anomaly shows that entanglement and non-locality are not only different concepts, but also truly different resources. We review the present knowledge on this anomaly, point out that Hardy's theorem has the same feature, and discuss the perspectives opened by these discoveries.

scholarly journals Operational approach to entanglement and how to certify it

2016 ◽  
Vol 14 (04) ◽  
pp. 1640003 ◽  
Author(s):  
M. Kupczynski
Keyword(s):  
Quantum Physics ◽  
Statistical Significance ◽  
Quantum States ◽  
Entangled States ◽  
Sufficient Condition ◽  
Significance Tests ◽  
Operational Approach ◽  
Physical Systems ◽  
Quantum Phenomenon ◽  
Sample Homogeneity

Entangled physical systems are an important resource in quantum information. Many papers were published trying to grasp the meaning of entanglement. It was noticed that a Hilbert space of possible state vectors of compound physical system can be partitioned by introducing various tensor product structures induced by the experimentally accessible observables (interactions and measurements). In this sense, the entanglement is relative to a particular set of experimental capabilities. Inspired by these results some authors claim that in fact all quantum states are entangled. In this paper, we show that this claim is incorrect and we discuss in operational way differences existing between separable and entangled states. A sufficient condition for entanglement is the violation of Bell–CHSH-CH inequalities and/or steering inequalities. Since there exist experiments outside the domain of quantum physics violating these inequalities therefore in the operational approach one cannot say that the entanglement is an exclusive quantum phenomenon. We also explain that an unambiguous experimental certification of the entanglement is a difficult task because classical statistical significance tests may not be trusted if sample homogeneity cannot be tested or is not tested carefully enough.

scholarly journals Quantum Correlations and Permutation Symmetries

2018 ◽  
Author(s):  
Mrittunjoy Guha Majumdar
Keyword(s):  
Quantum System ◽  
Graphical Method ◽  
Quantum Correlations ◽  
Quantum States ◽  
Matrix Analysis ◽  
Reduced Density Matrix ◽  
Density Matrices ◽  
Quantum Non Locality ◽  
Reduced Density ◽  
Non Locality

In this paper, the connections between quantum non-locality and permutation symmetries areexplored. This includes two types of symmetries: permutation across a superposition and permutationof qubits in a quantum system. An algorithm is proposed for nding the separability class ofa quantum state using a method based on factorizing an arbitrary multipartite state into possiblepartitions, cyclically permuting qubits of the vectors in a superposition to check which separabilityclass it falls into and thereafter using a reduced density-matrix analysis of the system is proposed.For the case of mixed quantum states, conditions for separability are found in terms of the partialtransposition of the density matrices of the quantum system. One of these conditions turns out tobe the Partial Positive Transpose (PPT) condition. A graphical method for analyzing separabilityis also proposed. The concept of permutation of qubits is shown to be useful in dening a newentanglement measure in the `engle'.

Quantum Becoming?

2017 ◽  
Author(s):  
Craig Callender
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Quantum Time ◽  
Quantum Non Locality ◽  
Time Quantum ◽  
Temporal Becoming ◽  
Non Locality ◽  
Quantum Wavefunction

Two of quantum mechanics’ more famed and spooky features have been invoked in defending the idea that quantum time is congenial to manifest time. Quantum non-locality is said by some to make a preferred foliation of spacetime necessary, and the collapse of the quantum wavefunction is held to vindicate temporal becoming. Although many philosophers and physicists seek relief from relativity’s assault on time in quantum theory, assistance is not so easily found.

Control of Förster energy transfer in the vicinity of metallic surfaces and hyperbolic metamaterials

2015 ◽  
Vol 178 ◽  
pp. 395-412 ◽  
Author(s):  
T. U. Tumkur ◽  
J. K. Kitur ◽  
C. E. Bonner ◽  
A. N. Poddubny ◽  
E. E. Narimanov ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Spontaneous Emission ◽  
Practical Importance ◽  
Index Of Refraction ◽  
Metallic Surfaces ◽  
Dielectric Media ◽  
Plasmonic Structures ◽  
Donor And Acceptor ◽  
Förster Energy Transfer ◽  
Photonic States

Optical cavities, plasmonic structures, photonic band crystals and interfaces, as well as, generally speaking, any photonic media with homogeneous or spatially inhomogeneous dielectric permittivity (including metamaterials) have local densities of photonic states, which are different from that in vacuum. These modified density of states environments are known to control both the rate and the angular distribution of spontaneous emission. In the present study, we question whether the proximity to metallic and metamaterial surfaces can affect other physical phenomena of fundamental and practical importance. We show that the same substrates and the same nonlocal dielectric environments that boost spontaneous emission, also inhibit Förster energy transfer between donor and acceptor molecules doped into a thin polymeric film. This finding correlates with the fact that in dielectric media, the rate of spontaneous emission is proportional to the index of refractionn, while the rate of the donor–acceptor energy transfer (in solid solutions with a random distribution of acceptors) is proportional ton−1.5. This heuristic correspondence suggests that other classical and quantum phenomena, which in regular dielectric media depend onn, can also be controlled with custom-tailored metamaterials, plasmonic structures, and cavities.

Introduction, generation and entanglement of entangled displaced even and odd squeezed states

2021 ◽  
pp. 2050047
Author(s):  
Amir Karimi
Keyword(s):  
Quantum States ◽  
Entangled States ◽  
Squeezed States ◽  
Displacement Operator ◽  
Text Type ◽  
Level Atom ◽  
Displacement Parameter ◽  
Entangled Quantum States ◽  
Quantized Field ◽  
Classical Fields

In this paper, first, we introduce special types of entangled quantum states named “entangled displaced even and odd squeezed states” by using displaced even and odd squeezed states which are constructed via the action of displacement operator on the even and odd squeezed states, respectively. Next, we present a theoretical scheme to generate the introduced entangled states. This scheme is based on the interaction between a [Formula: see text]-type three-level atom and a two-mode quantized field in the presence of two strong classical fields. In the continuation, we consider the entanglement feature of the introduced entangled states by evaluating concurrence. Moreover, we study the influence of the displacement parameter on the entanglement degree of the introduced entangled states and compare the results. It will be observed that the concurrence of the “entangled displaced odd squeezed states” has less decrement with respect to the “entangled displaced even squeezed states” by increasing the displacement parameter.

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