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Journal of Student Research

One-Way Speed of Light Experiment (Quantum Entanglement Approach)

Dhruv Agarwal, Kristine Rezai

Published May 31, 2022• 0 citations
Publisher

Abstract

Since Einstein stated the constancy of the speed of light to be a mere “stipulation … to arrive at a definition of simultaneity”, theorists argued that it could be possible for the speed of light to differ in different directions since there are many anisotropies like the amount of matter vs antimatter. However, this assumption has not been confirmed yet. No experiment has been proposed that measures the one-way speed of light; all experiments to date measure the round-trip speed of light. The experiment proposed in this paper seeks to measure the one-way speed of light by using an entanglement-controlled stopwatch while remaining blind (during the experiment) on whether the speed of light is isotropic or anisotropic, thereby answering the century-long question.

DOI
10.47611/jsrhs.v11i2.2540

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Since Einstein stated the constancy of the speed of light to be a mere “stipulation … to arrive at a definition of simultaneity”, theorists argued that it could be possible for the speed of light to differ in different directions since there are many anisotropies like the amount of matter vs antimatter. However, this assumption has not been confirmed yet. No experiment has been proposed that measures the one-way speed of light; all experiments to date measure the round-trip speed of light. The experiment proposed in this paper seeks to measure the one-way speed of light by using an entanglement-controlled stopwatch while remaining blind (during the experiment) on whether the speed of light is isotropic or anisotropic, thereby answering the century-long question.
One of the main issues in measuring the speed of light when it only travels from one spatial position into another position, known as the one-way speed of light, is that the clocks belonging to each separated spatial position are not and, in principle, cannot be synchronized. Here, we show that it is possible, in principle, to measure the velocity of particles that travel at the speed of light without assuming a round-trip once we adopt a quantum mechanical description under two boundary conditions to the state of the quantum system followed by the two-state-vector formalism while assuming non-synchronized quantum clocks with unknown time dilation. The weak value of velocity can be measured for a test particle that has a clock that is not synchronized with the clock of the quantum particle. Following the proposed set-up, when the weak value of the velocity is known even without knowing the time states of the system, such a weak velocity is the two-way speed of light. We further explore some fundamental implications of the set-up. The proposed approach opens a new avenue toward measuring the velocities of quantum particles while overcoming relativistic issues regarding the synchronization of clocks.
The origin and elaboration of our fundamental theories like quantum theory, the theory of relativity and the quantum field theories can be traced to the study of light and its properties. While developing these theories, several notions on the behaviour of light have been hypothesized as well as asserted, sometimes without any direct or compelling empirical evidence. In the context of quantum physics, there is a widespread belief that experiments on quantum correlations establish nonlocality as an essential aspect of nature. Another unshakable belief without direct empirical support is the absolute constancy of the speed of light relative to moving observers. In this paper, I argue that no experiment on quantum correlations of spatially separated photons necessitates the concept of nonlocality, and that there is no direct empirical proof of nonlocality. I also comment on the need to modify established notions on quantum light, in the context of a clear conflict between cosmology and the zero point energy of quantum electrodynamics. Then I describe the first experiments on the measurement of the true one-way speed light relative to a reference platform that is in inertial motion. The results are at variance with the belief that the speed of light is independent of the velocity of the observer.
In a rod of length AB =L= L=L, rotating uniformly, any two spatially separated points along the rod are connected in a way that shows analogies with the quantum entanglement of the spin of particles. This ”classical entanglement” reflects the simultaneity preset in the system, which can be used for syncing two distant clocks, one at A and the other at B. Since it differs from Einstein synchronization, this procedure can be adopted for testing the one-way light speed and Lorentz invariance. Applications to optical Sagnac effects confirm that a consistent interpretation requires the adoption of absolute versus relative simultaneity.
In a rod of length AB =L= L=L, rotating uniformly, any two spatially separated points along the rod are connected in a way that shows analogies with the quantum entanglement of the spin of particles. This ”classical entanglement” reflects the simultaneity preset in the system, which can be used for syncing two distant clocks, one at A and the other at B. Since it differs from Einstein synchronization, this procedure can be adopted for testing the one-way light speed and Lorentz invariance. Applications to optical Sagnac effects confirm that a consistent interpretation requires the adoption of absolute versus relative simultaneity.
In a rod of length AB =L= L=L, rotating uniformly, any two spatially separated points along the rod are connected in a way that shows analogies with the quantum entanglement of the spin of particles. This ”classical entanglement” reflects the simultaneity preset in the system, which can be used for syncing two distant clocks, one at A and the other at B. Since it differs from Einstein synchronization, this procedure can be adopted for testing the one-way light speed and Lorentz invariance. Applications to optical Sagnac effects confirm that a consistent interpretation requires the adoption of absolute versus relative simultaneity.
The speed of light, c, is the best-confirmed constant in physics. Within Special Relativity, it defines the causal structure of spacetime and no experiment has ever recorded an object exceeding it. This paper does not dispute any of that. What this paper argues is that quantum entanglement constitutes direct experi­mental evidence that the extrapolation of c to a universal limit across all layers of physical reality is not justified by the data. c is the fundamental limit of rel­ativistic spacetime. Whether it is also the limit of whatever substrate gives rise to that spacetime is a question the experiments force us to take seriously—and that current physics leaves genuinely open. Bell-test experiments, confirmed from Aspect (1982) to the Large Hadron Col­lider (2023), show that entangled correlations cannot be explained by any local model. Something produces those correlations without any mechanism that re­spects c. The no-communication theorem shows that this cannot be exploited for signalling today, within the current framework. It does not show that c gov­erns the mechanism that produces the correlations. Those are different claims, and conflating them has allowed a mathematical result about signal statistics to carry unwarranted ontological weight. This is a conceptual and philosophical analysis grounded in experimental results. It does not propose a new theory. It argues that the evidence we already have is sufficient to challenge the extrapolation that treats c as an absolute limit across all layers of physical reality. That extrapolation is not forced by the data. It is a theoretical choice and a contestable one.