Building on the recent proposal that a single ``bona fide'' clock suffices to define spacetime's metric, we introduce an Entangled Clock protocol based on singlet-state correlations. Invoking Zeilinger's Foundational Principle, we argue that while the local flow of time, operationally defined as a sequence of detector ``ticks,'' is irreducibly random (one bit per elementary system), the synchronized flow between spatially separated observers depends on their measurement geometry. Comparing the quantum prediction for the coincidence rate with Peres' classical ``bomb fragment'' model, we find that at obtuse relative angles the entangled clock exhibits a 13 percent higher synchronized tick rate than this linear classical benchmark. This ``temporal acceleration'' is linked to contextuality: following Peres, ``unperformed experiments have no results,'' and quantum systems are not constrained to maintain consistency with all counterfactual measurement settings. We stress, however, that for any single measurement angle a suitably tailored classical model can reproduce the quantum rate. The genuinely nonclassical character of the entangled clock emerges only when correlations at several angles are considered simultaneously and are shown to violate Bell-type inequalities. In this sense, the violation of Bell-type bounds serves as a certification that the shared time standard is genuinely quantum.
Building on the recent proposal that a single bona fide'' clock suffices to define spacetime's metric, we introduce an Entangled Clock protocol based on singlet-state correlations. Invoking Zeilinger's Foundational Principle, we argue that while the local flow of time, operationally defined as a sequence of detector ticks,'' is irreducibly random (one bit per elementary system), the synchronized flow between spatially separated observers depends on their measurement geometry. Comparing the quantum prediction for the coincidence rate with Peres' classical bomb fragment'' model, we find that at obtuse relative angles the entangled clock exhibits a 13 percent higher synchronized tick rate than this linear classical benchmark. This temporal acceleration'' is linked to contextuality: following Peres, ``unperformed experiments have no results,'' and quantum systems are not constrained to maintain consistency with all counterfactual measurement settings. We stress, however, that for any single measurement angle a suitably tailored classical model can reproduce the quantum rate. The genuinely nonclassical character of the entangled clock emerges only when correlations at several angles are considered simultaneously and are shown to violate Bell-type inequalities. In this sense, the violation of Bell-type bounds serves as a certification that the shared time standard is genuinely quantum.
One of the striking properties of quantum mechanics is the occurrence of the Bell-type non-locality. They are a fundamental feature of the theory that allows two parties that share an entangled quantum system to observe correlations stronger than possible in classical physics. In addition to their theoretical significance, non-local correlations have practical applications, such as device-independent randomness generation, providing private unpredictable numbers even when obtained using devices delivered by an untrusted vendor. Thus, determining the quantity of certifiable randomness that can be produced using a specific set of non-local correlations is of significant interest. First, we present an experimental realization of recent Bell-type operators designed to provide private random numbers that are secure against adversaries with quantum resources. We use semi-definite programming to give lower bounds on the generated randomness in terms of both min-entropy and von Neumann entropy in a device-independent scenario. Our results demonstrate the first experiment that certifies nearly two bits of randomness from binary measurements of two parties [1], [2]. Apart from single-round certification, we provide an analysis of finite-key protocol for quantum randomness expansion using the Entropy Accumulation Theorem. Second, we present an efficient and practical method for certifying quantum randomness using generalized measurements. Indeed, we have derived a method for self-testing the presence of POVMs. We present the certification of more than one bit of min-entropy from a single POVM on one of the qubits of an entangled state using a variant of the elegant Bell inequality. We also obtain more than one bit of randomness in a prepare and measure scenario of a similar structure with a POVM on a single qubit [3]. We provide numerical simulations to demonstrate the effectiveness of our randomness certification and expansion.
Abstract One of the striking properties of quantum mechanics is the occurrence of the Bell-type non-locality. They are a fundamental feature of the theory that allows two parties that share an entangled quantum system to observe correlations stronger than possible in classical physics. In addition to their theoretical significance, non-local correlations have practical applications, such as device-independent randomness generation, providing private unpredictable numbers even when they are obtained using devices delivered by an untrusted vendor. Thus, determining the quantity of certifiable randomness that can be produced using a specific set of non-local correlations is of significant interest. In this paper, we present an experimental realization of recent Bell-type operators designed to provide private random numbers that are secure against adversaries with quantum resources. We use semi-definite programming to provide lower bounds on the generated randomness in terms of both min-entropy and von Neumann entropy in a device-independent scenario. We compare experimental setups providing Bell violations close to the Tsirelson’s bound with lower rates of events, with setups having slightly worse levels of violation but higher event rates. Our results demonstrate the first experiment that certifies close to two bits of randomness from binary measurements of two parties. Apart from single-round certification, we provide an analysis of finite-key protocol for quantum randomness expansion using the Entropy Accumulation theorem and show its advantages compared to existing solutions.
By combining the assumptions of Bell locality with those of generalized noncontextuality, we define classes of noncontextuality inequalities for correlations arising in a bipartite Bell circuit. These classes are distinguished by which subsets of the full set of operational identities are taken as input to the principle of noncontextuality; certain natural subsets form a hierarchy that provides a way of understanding and classifying different forms of quantum correlations, including entanglement, steering, and nonlocality. Each level of this hierarchy gives rise to a corresponding class of noncontextuality inequalities whose violation witnesses one of these forms of bipartite quantum resourcefulness, thereby yielding different sufficient conditions for entanglement. The resulting entanglement certification paradigm requires no prior characterization of the measurements, delivers a verdict independent of tomographic gauge freedom, and can certify any entangled state without auxiliary entangled sources. To illustrate the power of this paradigm, we show that noncontextuality inequalities can certify entanglement for families of two-qubit isotropic states for which certification by Bell or steering inequalities is known to be impossible. We also show that, compared with the Bell test, this approach certifies a much larger fraction of entangled states, while the associated membership problem is computationally more tractable. On the experimental side, we describe techniques to ensure nontrivial operational identities in the presence of noisy and imperfect implementations. We also identify the sufficient condition under which these techniques are valid, namely, a particular notion of of the implemented Bell circuit, which ensures that the operational identities are independent of tomographic gauge. Finally, we provide an experimental demonstration of the superior performance of this entanglement certification technique using polarization-entangled photons.
Time is typically treated as a fundamental background parameter or as an emergent property arising from thermodynamic or geometric considerations. In this report we explore a different origin: the generation of time through asymmetric quantum entanglement. A symmetrically entangled pair possesses exchange-indistinguishability; its joint dynamics yield no relational change and therefore no internal temporal reference. However, when symmetry is broken—through a structural or dynamical asymmetry applied to one member of the pair—the correlations between the two subsystems evolve non-identically while remaining entangled. This relational change provides the minimal operational signature of a “tick,” offering a microscopic mechanism for the emergence of time. We construct and analyse a minimal asymmetric entanglement unit comprising an A–B entangled pair and a third system C that couples asymmetrically to A. Numerical simulations of this triplet demonstrate coherent periodic structure in both the trace distance of B relative to its symmetric evolution and in the concurrence of the A–B entanglement scaffold. These oscillations constitute a locally generated temporal reference. We then extend this model to chains of multiple A–B–C units and show that locally generated ticks propagate through neighboring cells, giving rise to a smooth temporal density field along the chain. This illustrates a potential pathway by which microscopic asymmetry-induced ticks may accumulate to form a macroscopic temporal frame. Although exploratory in scope, this work provides one of the most explicit and operational demonstrations to date of how time may arise from purely quantum-mechanical processes. The model highlights asymmetric entanglement as a plausible generator of temporal structure and lays the groundwork for coarse-grained temporal field theories and potential connections to gravitational time dilation.
Abstract A major outstanding problem for many quantum clock synchronization protocols is the hidden assumption of a common phase reference between the parties to be synchronized. In general, the definition of the quantum states between two parties do not have consistent phase definitions, which can lead to an unknown systematic error. We show that despite prior arguments to the contrary, it is possible to remove this unknown phase via entanglement purification. This closes the loophole for entanglement based quantum clock synchronization protocols, which is a non-local approach to synchronize two clocks independent of the properties of the intervening medium. Starting with noisy Bell pairs, we show that the scheme produces a singlet state for any combination of (i) differing basis conventions for Alice and Bob; (ii) an overall time offset in the execution of the purification algorithm; and (iii) the presence of a noisy channel. Error estimates reveal that better performance than existing classical Einstein synchronization protocols should be achievable using current technology.
Abstract Einstein, Podolsky and Rosen argued in 1935 that quantum mechanics must be incomplete: if measuring one member of a correlated pair lets you predict the result of measuring the other, the second particle must already possess that property. Bohr’s reply, published the same year, rejected the premise — a physical property, he argued, is not well defined independently of the experimental arrangement used to determine it. That reply has stood for ninety years primarily as a philosophical stance rather than a mathematical one. This paper makes Bohr’s relational reply mathematically precise, and then extends it into a separate, falsi- fiable physical hypothesis. The entangled pair is represented not by two separate local properties but by a single non-separable relational object — the correlation tensor of the joint state — and we show explicitly, via the vanishing local Bloch vectors of the singlet state, that no information whatsoever exists at either particle in isolation. “Meaning,” in the sense of a definite, locally accessible outcome, is then generated only through the local interaction between this joint resource and a physical interpreter; we prove that this construction reproduces the maximal quantum (Tsirelson-bound) violation of the CHSH inequality while remaining fully consistent with the no-communication theorem, and we prove a general lemma showing that no purely local extension of a hidden-variable model — regardless of how many additional local arguments, including an explicit interpreter variable, are added to it — can do the same. We further show that a natural strengthening of the interpreter concept — treating interpretation as a discrete, threshold-gated event rather than a continuous quantity — reproduces the classical detection (fair-sampling) loophole first identified by Pearle unless interpreter efficiency exceeds the Clauser–Horne bound, and we state that condition explic- itly as part of the hypothesis rather than leaving it implicit. This is the weak hypothesis: an interpretive, quantitatively grounded formalization of relational quantum mechanics, introducing no new physics. The paper then asks a separate, genuinely new question: once a local record of an interaction is estab- lished, does its persistence, accessibility, and redundancy have any further physical consequence beyond ordinary decoherence? We propose a specific, minimal dynamical ansatz — a local dephasing term pro- portional to a measurable record-establishment index — construct explicit toy Hamiltonians proving both that a naive downstream test of this idea is logically invalid (by the no-communication theorem) and that a concurrent-protocol replacement is logically coherent, and derive a quantitative experimental target for a superconducting-qubit implementation. This strong hypothesis is falsifiable and, unlike the weak hypothesis, is not already implied by orthodox quantum mechanics. Keywords: quantum foundations; EPR; Bell’s theorem; Bohr; relational quantum mechanics; entanglement; correlation tensor; decoherence; Quantum Darwinism; phenomenological modifications of quantum mechan- ics. AI assistance. This manuscript was developed through extensive collaborative dialogue with multiple AI systems — Claude (Anthropic), ChatGPT (OpenAI), and Gemini (Google DeepMind) — each used in a substantive capacity: deriving and stress-testing the mathematical arguments of Sections 2–4 and 8– 9 — including the CHSH local-extensibility lemma of Section 2.3, the correlation-tensor formalization of Section 3, the no-signaling proof of Appendix A, and the toy-Hamiltonian existence proofs of Section 9 — identifying and correcting several formulations that arose during development and were later shown to be untenable (including local hidden-variable constructions excluded by Bell’s theorem, and a threshold- based interpreter model shown to reproduce the classical detection loophole of Pearle and Clauser–Horne), and manuscript drafting throughout. Citation verification — confirming that cited sources exist and are represented accurately — and the mathematical derivations themselves were performed primarily by these AI systems, including AI-executed literature searches; the author directed the inquiry, exercised judgment over which lines of reasoning to pursue and what to include, and takes responsibility for the final content, but did not independently re-derive the mathematics or re-verify the primary sources. This manuscript has not undergone external peer review. Full context: https://www.linkedin.com/pulse/im-physicist-heres-what-happened-when-i-tried-turn-ai-ruiz-izaguirre-6012c/