Feynman’s Quantum Electrodynamics was developed by considering the reversion in time, which means that there is a violation in the causality: something in the future yields a happening in the past. Here we show that the paradox exists when one tries to understand the electron’s motion through a classical trajectory. However, by considering that the electron actually moves through a helical trajectory, the success of Feynman’s theory can be explained without considering the reversion in time.
Feynman’s Quantum Electrodynamics was developed by considering the reversion in time, which means that there is a violation in the causality: something in the future yields a happening in the past. Here we show that the paradox exists when one tries to understand the electron’s motion through a classical trajectory. However, by considering that the electron actually moves through a helical trajectory, the success of Feynman’s theory can be explained without considering the reversion in time.
This paper reinterprets Richard Feynman's use of negative time within quantum electrodynamics (QED) through the lens of the "Special Time Loop Paradox" (STLP), a thought experiment designed to expose logical contradictions in time-reversal scenarios involving faster-than-light motion.While QED remains one of the most accurate and successful physical theories in terms of experimental predictions, we argue that its reliance on mathematical devices-particularly time-reversed solutions-hints at a deeper incompleteness.Our analysis suggests that these "mathematical tricks" may not merely be calculational tools but indicators of a foundational limitation.
Quantum mechanics, even in its early and simple phases, has often been regarded as a non-causal discipline. The argument supporting this view cites the uncertainty principle as prohibiting the ascertainment of complete knowledge concerning physical states upon which causal prediction could be based. Recent developments in atomic physics have added new and puzzling features to the problem of causality insofar as they operate, not only with intrinsically unmeasurable states, but also with time reversals which have been interpreted to mean that the effect can be prior to the cause. Feynman's theory of quantum electrodynamics is particularly rich in unorthodox suggestions which tantalise philosophers. The purpose of the present paper is to exhibit them, appraise their methodological function and see in what manner they violate the rules of causal description. This purpose, it seems, is best achieved by a sequential discussion of three questions: What does causality mean in physics? What is the new method of quantum electrodynamics? Is this new method compatible with the causal doctrine in some satisfactory form?
It is brought forward that viable theories of the physical world that have no variable at all that can play the role of time, do not exist; some notion of time is one of the very first ingredients a candidate theory should possess. Almost by definition, time has an arrow. In contrast, time reversibility, or even the possibility to run the equations of motion backwards in time, is not at all a primary requirement. This means that the direction of the arrow of time may well be uniquely defined in the theory, even locally. It is explained that a rigorous definition of time, as well as a formulation of the causality and locality concepts, can only be given when one has a model for the physical phenomena described. The only viable causality condition is one that is symmetric under time reversal. We explain these statements in terms of the author’s favoured deterministic cellular automaton interpretation of quantum mechanics, also to be referred to as 'vector space analysis', and expand on these ideas. It is also summarised how our more rigorous causality condition affects Bell’s theorems. What distinguishes quantum systems from classical ones is our fundamental inability to control the microscopic details of the initial state when phenomena are studied in the light of some theoretical model.
In the book the idea of irreversibility as an inherent property of time is developed theoretically and experimentally. The matter is related with causality, and the method of causal analysis is presented. The quantum causal analysis helps understand the principle of week causality which admits extraction of information from the future without the classical paradoxes. It implies a possibility of observation of the future as the existing reality. So, the acceptance of time irreversibility leads to a striking manifestation of reversibility – signaling in reverse time. Quantum insight allows considering correlations of the distant irreversible processes as nonlocal ones originated from a macroscopic entanglement. The experimental approach to study of macroscopic nonlocality is discussed, and design of the experimental setup is described. The results of experiments on macroscopic nonlocal correlations, the signals in reverse time and their application to the forecast of large-scale random processes are expounded.
A new interpretation of quantum mechanics, similar to the Copenhagen interpretation, is developed from time-symmetry arguments and commonly held principles concerning time and causality. These principles, which are grounded in ideas outside of quantum mechanics, suggest that the strange features and paradoxes of quantum mechanics come from backward causation, in which future events can change the past. Using these principles this paper gives a better understanding of (and reasons for) stationary states, tunneling, wave-particle duality, the measurement problem with the collapse of the state vector, Hardy's paradox, non-locality, and the EPR paradox. These are only a few of the interpretational successes, and the model will be contrasted to other popular and/or recent interpretations. Unfortunately, this model is metaphysical, without any predictive power.
The rampant success of quantum theory is the result of applications of the 'new' quantum \nmechanics of Schrödinger and Heisenberg (1926-7), the Feynman-Schwinger-Tomonaga Quantum \nElectrodynamics (1946-51), the electro-weak theory of Salaam, Weinberg, and Glashow (1967-9), \nand Quantum Chromodynamics (1973-); in fact, this success of `the' quantum theory has depended \non a continuous stream of brilliant and quite disparate mathematical formulations. In this carefully \nconcealed ferment there lie plenty of unresolved difficulties, simply because in churning out fabulously \naccurate calculational tools there has been no sensible explanation of all that is going on. It is even \nargued that such an understanding is nothing to do with physics. A long-standing and famous \nillustration of this is the paradoxical thought-experiment of Einstein, Podolsky and Rosen (1935). \nFundamental to all quantum theories, and also their paradoxes, is the location of sub-microscopic \nobjects; or, rather, that the specification of such a location is fraught with mathematical inconsistency. \nThis project encompasses a detailed, critical survey of the tangled history of Position \nwithin quantum theories. The first step is to show that, contrary to appearances, canonical quantum \nmechanics has only a vague notion of locality. After analysing a number of previous attempts at a \n`relativistic quantum mechanics', two lines of thought are considered in detail. The first is the work \nof Wan and students, which is shown to be no real improvement on the usual `nonrelativistic' theory. \nThe second is based on an idea of Dirac's - using backwards-in-time light-cones as the hypersurface \nin space-time. There remain considerable difficulties in the way of producing a consistent scheme here. \nTo keep things nicely stirred up, the author then proposes his own approach - an adaptation \nof Feynman's QED propagators. \nThis new approach is distinguished from Feynman's since the propagator or Green's function \nis not obtained by Feynman's rule. The type of equation solved is also different: instead of an \ninitial-value problem, a solution that obeys a time-symmetric causality criterion is found for an \ninhomogeneous partial differential equation with homogeneous boundary conditions. \nTo make the consideration of locality more precise, some results of Fourier transform theory are \npresented in a form that is directly applicable. \nSomewhat away from the main thrust of the thesis, there is also an attempt to explain the \nmanner in which quantum effects disappear as the number of particles increases in such things as \nexperimental realisations of the EPR and de Broglie thought experiments.