Physicist Argues Quantum Coherence, Not Spooky Action, Explains Entanglement

A new perspective article published in the journal Discover Physics argues that the long-standing interpretation of quantum entanglement as an instantaneous connection between distant particles may be unnecessary. Xianming Meng, the paper’s author, contends that Bell test experiments, which are widely cited as proof of quantum entanglement, actually demonstrate something narrower: a rejection of local hidden variables and the existence of nonlocal correlation. According to the paper, that correlation can be fully explained by the quantum coherence of entangled particles combined with the shared physics of how particles interact with measuring instruments, without any superluminal influence or mysterious inner connection spanning the distance between them.

The argument begins with the history of the concept. Entanglement entered physics in 1935, when Albert Einstein, Boris Podolsky and Nathan Rosen published their famous paper arguing that wavefunctions do not contain complete information about a physical system, a claim later known as the EPR paradox. Einstein derided the apparent instantaneous influence of measuring one particle on its distant partner as spooky action at a distance. Erwin Schrödinger responded by coining the term entangled, and in 1964 John Bell proposed a statistical test of the paradox, later refined by Clauser, Horne, Shimony and Holt. Beginning with Alain Aspect’s experiments in the early 1980s, a long series of increasingly loophole-free Bell tests has consistently violated Bell’s inequality and matched the predictions of quantum mechanics.

Meng’s central point is about what those violations actually establish. The Bell inequality is derived under the assumption of local hidden variables, meaning variables confined to each measurement site. Violating it therefore rules out that specific class of explanation, but, the paper argues, it does not automatically endorse any inner connection between separated particles, such as superluminal communication or superposition spread over vast distances. The author goes further, arguing that the claimed instantaneous effect cannot even be verified in principle: any change in the state of the second particle can only be checked by measuring it, and measurement itself collapses the wavefunction and alters the state being checked, making the source of any observed correlation ambiguous.

The paper also scrutinises the two postulates sometimes offered to explain instantaneous influence. One is that information travels between entangled particles faster than light, which conflicts with the speed limit of relativity and becomes unphysical if instant means requiring infinite speed. The other is that superposition copies of each particle exist at every location, so no signal is needed. Meng accepts superposition in the microscopic world but rejects superposition of entangled particles across, say, millions of light-years as physically meaningful. Neither postulate, he concludes, is tenable, so the instantaneous-effect picture of entanglement lacks both a mechanism and empirical support.

The constructive part of the argument turns on coherence. In the paper’s usage, coherent particles are those whose phase difference is fixed. Entangled pairs are created through physical manipulations, such as laser or microwave pulses or pair production, that make the particles coherent, and the standard quantifiers of entanglement, including concurrence, skew information and von Neumann entropy, are all indicators of coherence or its deterioration. A simple thought experiment illustrates the equivalence: two photons of the same polarisation passing through two analysers will show strong correlations whether one assumes the first measurement changed the second photon, the entanglement claim, or assumes both photons simply pass their analysers easily because their polarisations align similarly with each analyser, the coherence claim. The operational predictions are identical, so the two explanations cannot be distinguished by the usual statistical correlation measurements.

The technical core of the paper works through the quantum calculation for an Aspect-style four-channel Bell test with polarised photon pairs. Starting from a maximally entangled Bell state in which the photon pair’s phases are fixed, rotating the analysers and applying the standard dot-product rule yields the well-known prediction that the coincidence expectation value equals the cosine of twice the relative angle between the two polarisers. Evaluating the Bell combination at analyser angles separated by multiples of pi over eight gives the maximal violation of two times the square root of two, exactly as experiments confirm. Meng emphasises that this derivation relies on three ingredients: the fully coherent initial state, the rotation and dot-product rules applied identically at both measurement stations, and the quantum rule that an operator acts only on the same basis, meaning a measurement at one location cannot act on the photon at the other.

That last rule carries the paper’s most striking implication. Because operators at one site act only on the local part of the entangled wavefunction, the formalism itself excludes the possibility that measuring one particle changes the quantum state of its distant partner. Measuring one entangled particle updates only the local part of the global state; the joint probability involving both sites naturally changes because it requires inputs from both locations. The nonlocal correlation instead arises from what Meng calls a global variable: the relative polarisation angle between the two analysers, together with the initial coherent state and the common measurement rules. He also argues that the Bell inequality derivation implicitly assumes locality, so introducing such shared global variables, like the relative analyser angle or the coincidence timing window, breaks the derivation and frees the results from the inequality’s constraint.

To show the result is not unique to quantum formalism, the paper reconstructs the same predictions semiclassically and statistically. A modified version of Malus’s law, the classical wave-optics rule for the amplitude of polarised light passing a polariser, applied to discrete photons and mapped onto the experimental value system reproduces the cosine prediction and the maximal violation at the same angles. A statistical treatment using vector rather than scalar correlation likewise yields the same expression, and more generally a correlation depending on the difference between the analyser angle and the photon pair’s own relative polarisation angle. When that pair angle difference is zero, the standard quantum prediction is recovered. The paper argues that intensity-based correlations, which some earlier analyses used, are inappropriate for Bell tests because they ignore the vector nature of polarisation and fall outside the required value range.

The paper closes with proposed thought experiments that could, in principle, settle the question experimentally. One setup places an extra pair of matched polarisers before the analysers with an unpolarised source, arranged so that one photon is measured before its partner reaches the second analyser. If spooky action were real, both detected intensities should fluctuate in synchrony; Malus’s law predicts only one should. A quantum-regime variant uses unequal source-to-polariser distances within an otherwise standard Bell test: if measurement of one photon shifted its partner’s polarisation, the optimal violation angles would shift or the correlation would vanish, whereas existing experiments with very large separations show no such sensitivity. Meng argues these results make the spooky-action hypothesis extremely unlikely, though the experiments remain proposals rather than performed tests.

It is worth underlining the status of these claims. The paper is a perspective article offering an interpretation, not a new experimental result, and its conclusion that the essence of quantum entanglement is quantum coherence is the author’s position rather than a consensus view; the mainstream reading of Bell tests as evidence of genuinely nonlocal quantum correlations remains dominant. What the article does establish is a careful technical case that the quantum formalism’s own rules, the semiclassical Malus’s-law account and a vector-correlation statistical approach all reproduce the observed Bell test correlations using only fixed relative phases, shared measurement rules and global setting variables, with no need for influence propagating between the particles. Whether the broader physics community accepts that reframing, and whether the proposed unequal-distance experiments are carried out, will determine if coherence can truly replace spookiness at the heart of entanglement.

Subject of Research: A theoretical reinterpretation of Bell test experiments arguing that quantum coherence, not spooky action at a distance, underlies quantum entanglement.

Article Title: Quantum coherence is the essence of quantum entanglement

Article References: Meng, X. (2026). Quantum coherence is the essence of quantum entanglement. Discover Physics, 2(1), Article 6. https://doi.org/10.1007/s44418-026-00007-x

Image Credits: AI Generated

DOI: 10.1007/s44418-026-00007-x

Keywords: quantum entanglement, quantum coherence, Bell tests, Bell inequality, EPR paradox, hidden variables, Malus's law, quantum optics, nonlocal correlation, polarisation, quantum foundations, Discover Physics