共查询到20条相似文献,搜索用时 15 毫秒
1.
P. K. Aravind 《Foundations of Physics Letters》2002,15(4):397-405
A proof of Bell's theorem without inequalities and involving only two observers is given by suitably extending a proof of the Bell-Kochen-Specker theorem due to Mermin. This proof is generalized to obtain an inequality-free proof of Bell's theorem for a set of n Bell states (with n odd) shared between two distant observers. A generalized CHSH inequality is formulated for n Bell states shared symmetrically between two observers and it is shown that quantum mechanics violates this inequality by an amount that grows exponentially with increasing n. 相似文献
2.
Bell's inequalities and related inequalities of Wigner, Clauser–Horne–Shimony–Holt, Accardi–Fedullo, Gudder–Zanghi, Herbert–Peres,
Khrennikov, others, are shown to be contained within a general operator trigonometry developed by this author starting in
1967. These inequalities are improved here to useful quantum spin correlation identities. Secondly, the Zeno problems from
quantum measurement theory are traced from early work by this author starting in 1974, to the present. A Zeno Alternative
that stresses domain-theoretic properties as essential to distinguishing reversible from irreversible quantum evolutions is
presented.
PACS: 03.65.Ud, 03.65.Xp,02.30.Tb. 相似文献
3.
A state-dependent proof of Bell's theorem without inequalities
using the product state of any two maximally entangled states
(Bell states) of two qubits for two observers in an ideal condition,
each of which possesses two qubits, is proposed. It is different
from the other proofs in which there exists a fundamental requirement
that certain specific suitable Bell states have been chosen.
Moreover, in any non-ideal situation, a common Bell inequality
independent of the choices of the 16-product states is derived,
which is used to test the contradiction between quantum mechanics
and local reality theory in the reach of current experimental technology. 相似文献
4.
G. Chen M.-M. He J.-Q. Li J.-Q. Liang 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(1):25-27
In this paper we investigate entanglement between the nuclear
spin and field mode in a GaAs semiconductor. The eigenfuctions of nuclear spin
in the quantized external field are obtained and thus the von Neumann
entropy is evaluated explicitly. It is shown that the von Neumann entropy
monotonously increases with the spin-field coupling constant but
monotonously decreases with the anisotropy energy. 相似文献
5.
Fabio Antonio Bovino 《International Journal of Theoretical Physics》2008,47(8):2148-2157
Nonlinear inequalities based on the quadratic Renyi entropy for mixed two-qubit states are characterized on the Entropy-Concurrence
plane. This class of inequalities is stronger than Clauser-Horne-Shimony-Holt (CHSH) inequalities and, in particular, is violated
“in toto” by the set of Type I Maximally-Entangled-Mixture States (MEMS I). 相似文献
6.
X. Hao S. Zhu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(1):199-203
The two atoms in the ion trap are entangled by the interaction
with an external excited atom. The evolution of the entanglement
is analytically derived without the decoherence. Considering the
spontaneous decay from the environment, the evolution of the
entanglement is similar to the damping Rabi oscillation. The
generation of entanglement is induced by the dipole-dipole type
interaction of atoms. It is found that the entanglement of two
trapped atoms is robust with the uniform interaction with the
external atom. The collective spontaneous emission from the
coupling between the atoms may enhance the entanglement. 相似文献
7.
Emilio Santos 《International Journal of Theoretical Physics》2003,42(10):2545-2555
We study the relation between the Bell inequalities—characteristic of noncontextual hidden variables theories of quantum mechanics—with quantum logic, quantum probability, and quantum information. The emphasis is on clarity and simplicity, although sometimes this implies a lack of mathematical rigor which, I hope, could be resolved without difficulty by the reader. 相似文献
8.
The quantum vacuum is unstable under the influence of an external electric field and decays into pairs of charged particles, a process which is known as the Schwinger pair production. We propose and demonstrate that this electric field can generate entanglement. Using the Schwinger pair production for constant and pulsed electric fields, we study entanglement for scalar particles with zero spins and Dirac fermions. One can observe the variation of the entanglement produced for bosonic and fermionic modes with respect to different parameters. 相似文献
9.
Sylvia Pulmannová 《Foundations of Physics》2002,32(2):193-216
In the quantum logic approach, Bell inequalities in the sense of Pitowski are related with quasi hidden variables in the sense of Deliyannis. Some properties of hidden variables on effect algebras are discussed. 相似文献
10.
Djeylan Aktas Bruno Fedrici Florian Kaiser Tommaso Lunghi Laurent Labont Sbastien Tanzilli 《Laser \u0026amp; Photonics Reviews》2016,10(3):451-457
Granting information privacy is of crucial importance in our society, notably in fiber communication networks. Quantum cryptography provides a unique means to establish, at remote locations, identical strings of genuine random bits, with a level of secrecy unattainable using classical resources. However, several constraints, such as non‐optimized photon number statistics and resources, detectors' noise, and optical losses, currently limit the performances in terms of both achievable secret key rates and distances. Here, these issues are addressed using an approach that combines both fundamental and off‐the‐shelves technological resources. High‐quality bipartite photonic entanglement is distributed over a 150 km fiber link, exploiting a wavelength demultiplexing strategy implemented at the end‐user locations. It is shown how coincidence rates scale linearly with the number of employed telecommunication channels, with values outperforming previous realizations by almost one order of magnitude. Thanks to its potential of scalability and compliance with device‐independent strategies, this system is ready for real quantum applications, notably entanglement‐based quantum cryptography.
11.
E. Santos 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):501-509
A family of local models containing two angles as hidden variables is
defined for experiments measuring polarization correlation of optical
photons. Searching for the best model of the family, that is giving
predictions most close to quantum mechanics, allows deriving Bell-type
inequalities which may be tested with relatively low detection efficiency. 相似文献
12.
Quantum state targeting is a quantum game which results from combining traditional quantum state estimation with additional
classical information. We consider a particular version of the game and show how it can be played with maximally entangled
states. The optimal solution of the game is used to derive a Bell inequality for two entangled qutrits. We argue that the
nice properties of the inequality are direct consequences of the method of construction. 相似文献
13.
K. Kraus 《Foundations of Physics Letters》1989,2(1):1-6
The question of whether or not the correlations predicted by quantum theory and actually observed in EPR-type experiments can be understood without assuming action at a distance is still controversial. The author's point of view, expressed by the title of this paper, is substantiated by the discussion of a specific example, and is defended against some recent criticism by H. P. Stapp.1. These predictions arenot exhausted by Eq. (1); see [9]. 相似文献
14.
The time-dependent quantum Monte Carlo method for fermions is introduced and applied in the calculation of the entanglement of electrons in one-dimensional quantum dots with several spin-polarized and spin-compensated electron configurations. The rich statistics of wave functions provided by this method allow one to build reduced density matrices for each electron, and to quantify the spatial entanglement using measures such as quantum entropy by treating the electrons as identical or distinguishable particles. Our results indicate that the spatial entanglement in parallel-spin configurations is rather small, and is determined mostly by the spatial quantum nonlocality introduced by the ground state. By contrast, in the spin-compensated case, the outermost opposite-spin electrons interact like bosons, which prevails their entanglement, while the inner-shell electrons remain largely at their Hartree–Fock geometry. Our findings are in close correspondence with the numerically exact results, wherever such comparison is possible. 相似文献
15.
16.
J. Gemmer G. Mahler 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(3):385-393
For a bi-partite quantum system defined in a finite dimensional Hilbert-space we investigate in what sense entanglement change
and interactions imply each other. For this purpose we introduce an entanglement-operator, which is then shown to represent
a non-conserved property for any bi-partite system and any type of interaction. This general relation does not exclude the
existence of special initial product states, for which the entanglement remains small over some period of time, despite interactions.
For this case we derive an approximation to the full Schr?dinger-equation, which allows the treatment of the composite systems
in terms of product states. The induced error is estimated. In this factorization-approximation one subsystem appears as an
effective potential for the other. A pertinent example is the Jaynes-Cummings model, which then reduces to the semi-classical
rotating wave approximation.
Received 8 June 2001 相似文献
17.
H. Fakhri S. K. A. Seyed Yagoobi M. Taqavi 《International Journal of Theoretical Physics》2006,45(11):2100-2108
In the present paper the integration region Λ with more than one hidden variable is attributed to a pair of particles in the Bell's thought experiment as the local causal events in their common lightcone. Moreover, the possibility of uncommon causal events influencing the spin measurement is not ignored. Then, with regard to the separability of the influence of the uncommon events from configuration of the setup, and by relying on local realism and coherency, each of the Bell's inequality versions is obtained by measuring spin in three and four different directions.
PACS numbers: 03.65.Ud 03.65.Ta. 相似文献
18.
Michel Feldmann 《Foundations of Physics Letters》1995,8(1):41-53
Using the new concept of "stochastic gauge system", we describe a novel loophole to circumvent the Einstein-Podolsky-Rosen (EPR) paradox. We derive a "realistic" (i.e., classical) model, free from any paradox, which exactly emulates the spin EPR experiment. We conclude that Bell's inequalities are violated in classical physics as well, or, conversely that quantum mechanical theory is logically consistent with relativity. 相似文献
19.
20.
D.G. Angelakis P.L. Knight 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):247-250
We show how entangled atomic pairs can be prepared in order to test the Bell inequalities. The scheme is based on the interaction
of the atoms with a highly localized field mode within a photonic crystal. The potential of using optically separated transitions
and the stability of the entangled state to spontaneous emission could lead to the closure of the communication and the detection
loopholes appearing in experiments so far. The robustness of the scheme against detector inefficiencies, the spread in the
atomic velocities and the fact that the entangled pairs are not generated simultaneously is also studied.
Received 31 July 2001 and Received in final form 30 November 2001 相似文献