scholarly journals Fundamental length, bubble electrons and non-local quantum electrodynamics. [Relativistic invariance, macrocausality, unitarity]

1977 ◽  
Author(s):  
J. P. Hsu ◽  
E. Mac
Keyword(s):  
Quantum Electrodynamics ◽  
Relativistic Invariance ◽  
Fundamental Length ◽  
Local Quantum ◽  
Non Local

scholarly journals Renormalization and conformal invariance of non-local quantum electrodynamics

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Matthew Heydeman ◽  
Christian B. Jepsen ◽  
Ziming Ji ◽  
Amos Yarom
Keyword(s):  
Conformal Invariance ◽  
Quantum Electrodynamics ◽  
Local Quantum ◽  
Non Local

Non-local quantum electrodynamics

1963 ◽  
Vol 7 (1) ◽  
pp. 36-38 ◽  
Author(s):  
M. Lévy
Keyword(s):  
Quantum Electrodynamics ◽  
Local Quantum ◽  
Non Local

On the choice of form factors in non-local quantum electrodynamics

1972 ◽  
Vol 44 (2) ◽  
pp. 541-557 ◽  
Author(s):  
G.V. Efimov ◽  
O.A. Mogilevsky
Keyword(s):  
Quantum Electrodynamics ◽  
Form Factors ◽  
Local Quantum ◽  
Non Local

Non-local quantum electrodynamics

1964 ◽  
Vol 57 ◽  
pp. 152-190 ◽  
Author(s):  
Maurice Lévy
Keyword(s):  
Quantum Electrodynamics ◽  
Local Quantum ◽  
Non Local

A simple non-local quantum electrodynamics

1956 ◽  
Vol 3 (2) ◽  
pp. 390-408 ◽  
Author(s):  
P. Sen
Keyword(s):  
Quantum Electrodynamics ◽  
Local Quantum ◽  
Non Local

scholarly journals Non-local quantum electrodynamics admits a finitely induced gauge field action

1995 ◽  
Vol 451 (1943) ◽  
pp. 571-577 ◽  
Keyword(s):  
Gauge Field ◽  
Quantum Electrodynamics ◽  
Local Action ◽  
Four Dimensions ◽  
Field Action ◽  
Local Quantum ◽  
Non Local ◽  
Non Locality

This paper reconsiders a result obtained by Chrétien & Peierls within non-local quantum electrodynamics in four dimensions (1954, Proc. R. Soc. Lond . A 223, 468). Starting from secondly quantized fermions, subject to a non-local action with the kernel [i∂ x a ( x ) - mb ( x )] and gauge covariantly coupled to an external U ﴾1﴿ gauge field, they found that, for a = b , the induced gauge field action cannot be made finite, irrespective of the choice of the non-locality a (= b ﴿. But, the general case studied a ≠ b admits a finitely induced gauge field action, as the present paper demonstrates.

scholarly journals Is Einsteinian no-signalling violated in Bell tests?

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 739-753 ◽  
Author(s):  
Marian Kupczynski
Keyword(s):  
Quantum Electrodynamics ◽  
Probability Distributions ◽  
Selection Procedure ◽  
Quantum Correlations ◽  
Spin Projection ◽  
Marginal Probability ◽  
Strong Correlations ◽  
Relativistic Invariance ◽  
Long Range Correlations ◽  
Apparent Violation

AbstractRelativistic invariance is a physical law verified in several domains of physics. The impossibility of faster than light influences is not questioned by quantum theory. In quantum electrodynamics, in quantum field theory and in the standard model relativistic invariance is incorporated by construction. Quantum mechanics predicts strong long range correlations between outcomes of spin projection measurements performed in distant laboratories. In spite of these strong correlations marginal probability distributions should not depend on what was measured in the other laboratory what is called shortly: non-signalling. In several experiments, performed to test various Bell-type inequalities, some unexplained dependence of empirical marginal probability distributions on distant settings was observed. In this paper we demonstrate how a particular identification and selection procedure of paired distant outcomes is the most probable cause for this apparent violation of no-signalling principle. Thus this unexpected setting dependence does not prove the existence of superluminal influences and Einsteinian no-signalling principle has to be tested differently in dedicated experiments. We propose a detailed protocol telling how such experiments should be designed in order to be conclusive. We also explain how magical quantum correlations may be explained in a locally causal way.

scholarly journals Local and Non-Local Invasive Measurements on Two Quantum Spins Coupled via Nanomechanical Oscillations

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1078
Author(s):  
Dimitrios Maroulakos ◽  
Levan Chotorlishvili ◽  
Dominik Schulz ◽  
Jamal Berakdar
Keyword(s):  
Quantum Coherence ◽  
Indirect Measurement ◽  
Quantum Spin ◽  
Quantum States ◽  
Spin Interaction ◽  
First Case ◽  
Composite Quantum System ◽  
Local Quantum ◽  
Non Local ◽  
Quantum Spins

Symmetry plays the central role in the structure of quantum states of bipartite (or many-body) fermionic systems. Typically, symmetry leads to the phenomenon of quantum coherence and correlations (entanglement) inherent to quantum systems only. In the present work, we study the role of symmetry (i.e., quantum correlations) in invasive quantum measurements. We consider the influence of a direct or indirect measurement process on a composite quantum system. We derive explicit analytical expressions for the case of two quantum spins positioned on both sides of the quantum cantilever. The spins are coupled indirectly to each others via their interaction with a magnetic tip deposited on the cantilever. Two types of quantum witnesses can be considered, which quantify the invasiveness of a measurement on the systems’ quantum states: (i) A local quantum witness stands for the consequence on the quantum spin states of a measurement done on the cantilever, meaning we first perform a measurement on the cantilever, and subsequently a measurement on a spin. (ii) The non-local quantum witness signifies the response of one spin if a measurement is done on the other spin. In both cases the disturbance must involve the cantilever. However, in the first case, the spin-cantilever interaction is linear in the coupling constant Ω , where as in the second case, the spin-spin interaction is quadratic in Ω . For both cases, we find and discuss analytical results for the witness.

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