We introduce a configuration‑dependent parametrisation of coherence in Wheeler’s delayed‑choice experiment based on the complex quantity T=t−iτ. The real component t retains its usual causal role, while the imaginary component τ encodes coherence attenuation without representing a physical time coordinate or an additional degree of freedom. Different interferometric configurations correspond to different decompositions of T, effectively acting as an internal rotation that modifies the imaginary‑time difference between paths and therefore the visibility. This mechanism alters coherence without affecting causal evolution and does not require retrocausality. The construction remains fully compatible with standard quantum mechanics: it preserves unitary evolution, the Born rule, and the structure of completely positive trace‑preserving maps, and is equivalent to a standard dephasing channel written in a compact parametrised form. The framework yields experimentally testable predictions for visibility modulation and temporal correlations, including a temporal CHSH protocol in which the departure from classical bounds arises from the configuration dependence of Δτ rather than from any modification of the underlying dynamics.
If we have to search an unsorted database or solve an unstructured search problem, we can use a quantum search algorithm. As of now, a quantum search algorithm like Grover's algorithm takes Ω(\sqrt N) time, where N is the size of the search space. This paper proposes an improved quantum search algorithm that yields the correct result in constant time with a high probability.
Quantum mechanics (QM) is an extremely successful theory, however, there is still no consensus regarding its interpretation. Among the controversies, the quantum classical transitions are the outstanding questions. In this paper, starting from measurement theory, we discuss the role that the precision limit for observation plays in QM and attempt to lubricate the relationship between the precision limit and some unique characters and nature of QM. By reviewing Bohmian mechanics, one of the nonlocal hidden variable theories, we discuss the possibility of restoring determinism in QM. We conclude that it is the existence of the precision limit that makes it impossible to restore determinism in QM, and it is the root that makes QM different from classical physics. Finally, the boundary between the so-called classical and quantum worlds is discussed. We hope these philosophical arguments can provide a kind of epistemic understanding for QM.
We deduce the quantum mechanical prediction of - a· b for the singlet spin state employing local measurement functions following Bell's approach. This result represents the quantum mechanical expectation value for the joint measurement of spin projections in the singlet state. And is equal to the negative cosine of the angle between vectors a and b. Our derivation is corroborated through a computational simulation conducted in the Mathematica programming environment using geometric algebra.
