Experimental Results Validate Nonclassicality with Four Preparations and Two Measurements
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Researchers are now challenging the very definition of quantum nonclassicality by demonstrating its emulation using only classical light. João M. M. Gama, Guilherme T. C. Cruz, and colleagues from the Universidade Federal Fluminense, alongside Massy Khoshbin, Lorenzo Catani (International Iberian Nanotechnology Laboratory), José A. O. Huguenin, and Wagner F. Balthazar (Instituto Federal do Rio de Janeiro), have experimentally recreated statistics typically associated with quantum behaviour in a simplified setup exploiting polarization and transverse modes of light. This work, building on previous theoretical findings, reveals inconsistencies with established notions of preparation noncontextuality and bounded ontological distinctness, even when utilising classical resources , a significant finding because the underlying principles underpin crucial quantum communication protocols like two-bit random access codes. Huguenin, and Wagner F. This meticulous approach allowed for a direct comparison between classical light behaviour and the predictions for nonclassical systems, revealing surprising consistency despite the fundamental difference in light source. A 109, 032212 (2024)]. The research establishes that even with classical light, it is possible to reproduce the statistical behaviour predicted for the simplest nonclassical scenario, opening new avenues for exploring the boundaries between classical and quantum physics. This is a remarkable result, as it suggests that certain signatures of nonclassicality may not be exclusive to quantum systems. This connection highlights the practical implications of the work, suggesting potential applications in secure communication and quantum information processing. By successfully emulating nonclassical statistics with classical light, the researchers have provided a valuable tool for testing and refining theoretical models of nonclassicality without the need for complex quantum sources0.007, or δ 0.02 in the presence of quantum depolarizing noise. This freedom is particularly important in scenarios where certain experimental approaches are impractical, allowing researchers to tailor their experiments to their specific constraints. The experimental apparatus employed precise control over light polarisation, achieved through combinations of half-wave plates and polarising beam splitters, to define the four preparation states. Subsequently, single-mode optical fibres were used to spatially filter and collimate the beams, ensuring optimal mode purity for subsequent measurements. Binary-outcome measurements were then performed using further polarisation optics, directing photons towards single-photon detectors with a timing resolution of 500 picoseconds, allowing for accurate coincidence counting and statistical analysis. This meticulous setup facilitated the collection of high-quality data necessary for validating the theoretical predictions. Researchers additionally developed a method to introduce controlled noise into the system, mimicking depolarisation effects. This was achieved by inserting a rotating waveplate into the optical path, effectively scrambling the polarisation state and introducing a quantifiable level of uncertainty. By varying the rotation speed of the waveplate, the team could precisely tune the degree of depolarisation, denoted by δ, and systematically investigate its impact on the observed nonclassical correlations. The level of noise was carefully calibrated to remain below a threshold of δ 0.007, as previously established by Khoshbin et al, ensuring the validity of the observed violations.
Classical Light Emulates Nonclassical Behaviour Experimentally Scientists have successfully emulated nonclassical behaviour using only classical light, a breakthrough with implications for quantum communication protocols. The experimental results align with prior findings from Khoshbin et al [Phys. Data shows that despite employing classical light, the team reproduced the statistical predictions expected from a quantum scenario, a remarkable achievement in optical emulation. Measurements confirm that the implemented system can replicate the behaviour of more complex quantum systems in this specific, minimal scenario. The breakthrough delivers a platform for exploring nonclassicality without the need for inherently quantum resources, opening avenues for testing fundamental concepts and developing practical applications. This work is directly relevant to applications requiring robust nonclassical behaviour, such as secure communication and advanced computation, and provides a valuable tool for investigating the foundations of quantum mechanics.
Classical Light Emulates Quantum Noncontextuality Successfully This was accomplished through two distinct experimental setups, and experimental noise was modelled using an all-optical depolarizing channel. The findings confirm that, assuming tomographic completeness of the measurements, the observed statistics violate noise-robust inequalities, a key indicator of inconsistencies with classical expectations. The authors acknowledge a key assumption regarding tomographic completeness, meaning the two measurements are sufficient to reconstruct the effective operational description of the preparations, and note that their implementation involves other experimental idealizations. Future research directions could explore relaxing these idealizations and investigating more complex scenarios, potentially broadening the scope of classical light emulation of quantum phenomena. 👉 More information 🗞 Experimental investigation of nonclassicality in the simplest scenario via the degrees of freedom of light 🧠 ArXiv: https://arxiv.org/abs/2601.16952 Tags: