Modeling of image transmission with a classic quantum computer interpreter is suggested.The transmission algorithm from the paper (Lemos G.B., et.al.Quantum Imaging with Undetected Photons, Nature, 2014, 512, P. 409-412) is modified to reduce the complexity of the quantum circuit.Simplification was done by replacing the non-linear optical elements with a conventional quantum entanglement operator.The obtained results show expected efficiency of data transmission with Gaussian beam by hypothesis test and calculation error function.This error function is used for quality measurement.The interpreter is written in Kotlin language.
Modeling of image transmission with a classic quantum computer interpreter is suggested.The transmission algorithm from the paper (Lemos G.B., et.al.Quantum Imaging with Undetected Photons, Nature, 2014, 512, P. 409-412) is modified to reduce the complexity of the quantum circuit.Simplification was done by replacing the non-linear optical elements with a conventional quantum entanglement operator.The obtained results show expected efficiency of data transmission with Gaussian beam by hypothesis test and calculation error function.This error function is used for quality measurement.The interpreter is written in Kotlin language.
This Spotlight aims to provide a general introduction to linear and nonlinear optical components that are frequently used to implement the protocols for quantum computation and communication. The role of each optical element is described briefly, and it is shown that these optical elements can be combined to constitute quantum circuits for performing various quantum computing and communication tasks. Present challenges and future scopes are also mentioned briefly. Specifically, after introducing the qubit, it is stated that a quantum gate is a device that transforms a quantum state into another quantum state. Thus, most of the optical components (e.g., a beamsplitter, a wave plate, a mirror, a polarizing beamsplitter) can be viewed as quantum gates because each of these optical elements can transform a quantum state into another quantum state. This fact is the basis for constructing useful quantum circuits using optical elements. Finally, a few proposals for optical realizations of schemes for quantum communication and computation are described.
In classical computation and communication, we use classical gates and bits. Similarly, in quantum computation and communication, we use their quantum analogs, i.e., quantum gates and qubit(s) [quantum bit(s)]. We have already mentioned that a bit can be realized in various ways. In the same way, a qubit can also be realized in various ways, and accordingly, corresponding quantum gates that would operate on qubits can also be realized in various ways. Here, we focus on a specific implementation: optical implementation, where qubits are realized using photons and quantum gates, and circuits are realized using various optical components. Specific merits of this realization lie in the following facts: (i) in quantum communication we need to transmit qubits from one location to the other, and transmission of photons is easier than any other realization of qubits; (ii) the effect of the environment (e.g., external electric and magnetic fields) on photons is less compared to any other implementations of qubits; and (iii) integrated optics are already a well-developed field. Keeping these points in mind, this Spotlight describes basic optical elements and how to use those elements to implement various schemes of quantum computation and communication. We will mostly describe realizations using bulk optics. However, in most cases, it is not difficult to transform these bulk-optics-based realizations into integrated optics. To begin with, in Section 1.1, we formally define a qubit and describe two alternative ways of realizing a qubit using a photon.
Barreto Lemos et al. [Nature 512, 409-412 (2014)] reported an experiment in which a non-degenerate parametric downconverter and a non-degenerate optical parametric amplifier--used as a wavelength-converting phase conjugator--were employed to image object transparencies in a manner akin to ghost imaging. Their experiment, however, relied on single-photon detection, rather than the photon-coincidence measurements employed in ghost imaging with a parametric downconverter source. More importantly, their system formed images despite the photons that passed through the object never being detected. Barreto Lemos et al. interpreted their experiment as a quantum imager, as assuredly it is, owing to its downconverter's emitting entangled signal and idler beams. We show, however, that virtually all the features of their setup can be realized in a quantum-mimetic fashion using classical-state light, specifically a pair of bright pseudothermal beams possessing a phase-sensitive cross correlation. Owing to its much higher signal-to-noise ratio, our bright-source classical imager could greatly reduce image-acquisition time compared to that of Barreto Lemos et al.'s quantum system, while retaining the latter's ability to image with undetected photons.
This article develops an expanded critical–propositional analysis of Gabriela Barreto Lemos et al.’s experiment, “Quantum Imaging with Undetected Photons,” published in Nature 512 (2014): 409–412, DOI 10.1038/nature13586, in systematic dialogue with the Theory of Objectivity (TO) formulated by Vidamor Cabannas and Denivaldo Silva. Lemos et al. experimentally demonstrated an imaging architecture based on induced coherence without induced emission in which photons that interact with an object are not themselves detected, whereas the image is reconstructed exclusively by detecting photons that never interacted directly with that object. Two coherently pumped nonlinear crystals can produce signal–idler photon-pair alternatives. An idler originating from the first crystal traverses the object and is subsequently mode- matched with the idler alternative associated with the second crystal. Under conditions in which the origin of the generated pair remains physically indistinguishable, the signal alternatives interfere, and amplitude and phase information introduced into the undetected idler path becomes accessible through the detected signal intensity (Lemos et al., 2014; Lahiri et al., 2015). The experiment therefore provides an unusually productive empirical domain in which to examine relations among interaction, physical distinguishability, coherence, information, observation, boundaries, and compositional phenomena. The present study argues that Lemos et al. do not experimentally establish the complete ontology of the Theory of Objectivity and do not demonstrate the modal necessity of its Seven Absolute Truths. Nevertheless, the experiment provides important operational bridges to the Fourth, Fifth, Sixth, and Seventh Absolute Truths when these propositions are carefully distinguished from stronger metaphysical interpretations. Particular attention is devoted to the Fifth Absolute Truth, according to which an element must, for logical existence, be observed or remain within the frequency of at least two other elements, where “observation” does not mean human consciousness. Quantum imaging with undetected photons provides an experimentally controlled domain in which observable manifestation depends on relations among multiple phys- ical systems independently of a conscious observer. The later theoretical analysis of the Lemos architecture showed that information about the object occurs in the interference contribution rather than in either individual signal intensity considered separately (Lahiri et al., 2015). This makes the experiment particularly relevant to a TO interpretation of information as fundamentally relational. Methodological restraint is nevertheless essential. Classical-state correlated optical systems can reproduce important operational features of imaging with unde- tected photons (Shapiro, Venkatraman, and Wong, 2015). Consequently, the Lemos experiment does not by itself discriminate between the ontology of the TO and all competing descriptions. Its strongest scientifically defensible role is therefore to provide a controlled experimental environment in which TO propositions concerning relational existence, physical boundaries, non-human observation, composition, and information may be translated into measurable quantities. The article concludes by proposing an empirical research program in which modal propositions of the TO are related to experimentally measurable parameters such as distinguishability, coherence, visibility, complex transmission, boundary transformation, and recoverable information. Such a program could move the TO from conceptual compatibility with quantum phenomena toward genuinely discriminating empirical predictions. Keywords: Theory of Objectivity; quantum imaging; undetected photons; induced co- herence; quantum information; relational information; observation; indistinguishability; modal ontology; physical boundaries; testability; transcendent information.
Summary form only given. Quantum computers are expected to increase the efficiency of solving problems such as factoring large integers. However an experimental implementation of even relatively simple quantum information processing with a few to a dozen qubits presents an enormous technological challenge. One of the earliest proposals for quantum computation is based on implementing a quantum bit with two optical modes containing one photon. The proposal is appealing due to the ease with which photon interference can be observed. However these early proposals required huge single photon optical nonlinearities. Unfortunately currently available optical nonlinearities are too weak and too noisy to be useful. Recently however we have discovered that efficient quantum computation is possible using only beam splitters, phase shifters, single photon sources and photodetectors. Our methods exploit feed forward from photo-detectors and are robust against errors from photon loss and detector inefficiency. In this tutorial I will outline this scheme, highlighting the technical challenges required to implement it. The tutorial will be relatively self contained with a brief introduction to quantum optics and quantum computation.
Abstract Text classification, a key process in natural language processing (NLP), relies on the k‐nearest neighbors (KNN) algorithm for its simplicity and effectiveness. Traditional methods often grapple with the high‐dimensional nature of textual data, leading to substantial computational demands. This study introduces a novel classical quantum k‐nearest neighbors (CQKNN) algorithm, which integrates quantum circuits into a conventional machine‐learning framework to enhance computational efficiency and reduce storage requirements. This hybrid approach uses a unified quantum circuit that simplifies multiple similarity calculations through mid‐circuit measurements and qubit reset operations, significantly improving upon traditional multi‐circuit quantum k‐nearest neighbors (QKNN) models. The CQKNN algorithm, tested on datasets such as SMS Spam Collection, Twitter US Airline Sentiment, and IMDB Movie Reviews, not only outperforms classical KNN but also addresses challenges posed by noisy intermediate‐scale quantum (NISQ) devices through advanced error mitigation techniques. This work highlights resource efficiency and reduced gate complexity and demonstrates the practical application of fidelity in quantum similarity calculations, setting new standards for quantum‐enhanced machine learning and advancing current quantum technology capabilities in complex data classification tasks.
Quantum entanglement distribution is an essential part of quantum communication and computation protocols. Here, linear optic elements are employed for distribution of quantum entanglement over long distance. Polarization beam splitters and wave plates are used for realization of an error-free protocol for broadcasting quantum entanglement in optical quantum communication. This protocol can determine maximum distance of quantum communication to transmit quantum information without decoherence. Error detection and error correction are performed in the proposed scheme. In other words, if bit-flip occurs along the quantum channel, the end stations (Alice and Bob) can detect this state changing and obtain the correct state (entangled photon) on the another port. Existing general error detection protocols are based on the quantum controlled-NOT (CNOT) or similar quantum logic operations, which are very difficult to implement experimentally. Here we present a feasible scheme for the implementation of entanglement distribution based on linear optics element that does not need quantum CNOT gate.