Search Results (7)

Currently, Kronecker Matrix–Matrix Multiplication play a crucial role in many advanced applications across science and engineering, such as Quantum Computing (Tensor Representation of Quantum States, Quantum Gate Construction), Machine Learning and Data Science (Kernel Methods, Tensor Decompositions), and Signal and Image Processing (Multi-dimensional Filtering, Compression Algorithms). However, the implementation of the Kronecker Matrix–Matrix Multiplication increasingly relies on systems with enhanced computational capabilities. Specifically, current implementations expend large amounts of external memory and requires a large number of processing units to perform this operation. As is commonly acknowledged, cutting-edge high-performance computing schemes still faces limitations in terms of energy and performance due to the bottleneck in data transfer between processing units and memory. To mitigate this limitation, memory processing units (MPUs) enable direct computation on in-memory data, reducing latency and eliminating the need for data transfer. On the other hand, spiking neural P systems, with their inherent parallelism and distributed processing capabilities, are therefore well-suited as foundational components for implementing such memory architectures efficiently. From the mathematical point of view, we present for the first time a neural, synaptic, and dendritic model to support the Kronecker Matrix–Matrix multiplication. To this end, the proposed spiking neural P system with their cutting-edge variants, such as anti-spikes, communication on request, synaptic weights, and dendritic–axonal delays, facilitates the creation of neural memory cells and spike-based routers. Hence, these elements potentially allow the design of novel processing memory architectures that markedly enhance data transfer efficiency between computational units and memory. Full article

This paper investigates the mathematical model of the quantum wavelength-division-multiplexing (WDM) network based on the entanglement distribution with the least required wavelengths and passive devices. By adequately utilizing wavelength multiplexers, demultiplexers, and star couplers, N wavelengths are enough to distribute the entanglement among each pair of N users. Moreover, the number of devices employed is reduced by substituting a waveguide grating router for multiplexers and demultiplexers. Furthermore, this study examines implementing the BBM92 quantum key distribution in an entangled-based quantum WDM network. The proposed scheme in this paper may be applied to potential applications such as teleportation in entangled-based quantum WDM networks. Full article

Time-correlated single-photon counting (TCSPC) is a powerful technique for time-resolved measurement of fast and weak light signals used in a variety of scientific fields, including biology, medicine, and quantum cryptography. Unfortunately, given its repetitive nature, TCSPC is recognized as a relatively slow technique. In the last ten years, attempts have been made to speed it up by developing multichannel integrated architectures. Yet, for the solutions proposed thus far, the measurement speed has not increased proportionally to the number of channels, reducing the benefits of a multichannel approach. Recent theoretical studies and prototypes have shown that it is possible to implement a new multichannel architecture, so-called router-based architecture, capable of optimizing the efficiency of data transfer from the integrated chip to the data processor, increasing the overall measurement speed. However, the first implementations failed to achieve the theoretical results due to implementation flaws. In this paper, we present a new logic for the router-based architecture that can operate at the same laser frequency and solve the issues of the previous implementation. Alongside the new logic, we present a new integrated low-jitter delay line combined with a new method for timing-signal distribution that allows the proper management of the pixel timing information. The new implementation is a step closer to realizing a router-based architecture that achieves the expected theoretical results. Simulations and bench tests support the results here reported. Full article

An ultra-compact optical quantum router (QR) consisting of a Mach–Zehnder interferometer (MZI) and waveguide tapers is proposed and numerically simulated, using silicon-on-insulator (SOI). The interferometer is designed to work at the center wavelength of 1550 nm with visibilities of 99.65% and 98.80% for TE and TM polarizations, respectively. Using the principle of phase compensation and self-image, the length of the waveguide tapers is shortened by an order of magnitude with the transmission above 95% for both TE and TM polarizations. Furthermore, polarization beam splitters (PBS) with an ultra-compact footprint of 1.4 × 10.4 μm² with transmissions of 98% for bi-polarizations are achieved by introducing anisotropic metamaterials. The simulated results indicate that the interferometer facilitates low loss, a broad operating spectral range, and a large tolerance to size variation in fabrications. The optical switch possesses the routing function while maintaining the polarization states, which promises to pave the point-to-point BB84 protocol into applications of network-based quantum communication. Full article

Quantum routers will provide for important functionality in emerging quantum networks, and the deployment of quantum routing in real networks will initially be realized on low-complexity (few-qubit) noisy quantum devices. A true working quantum router will represent a new application for quantum entanglement—the coherent superposition of multiple communication paths traversed by the same quantum signal. Most end-user benefits of this application are yet to be discovered, but a few important use-cases are now known. In this work, we investigate the deployment of quantum routing on low-complexity superconducting quantum devices. In such devices, we verify the quantum nature of the routing process as well as the preservation of the routed quantum signal. We also implement quantum random access memory, a key application of quantum routing, on these same devices. Our experiments then embed a five-qubit quantum error-correcting code within the router, outlining the pathway for error-corrected quantum routing. We detail the importance of the qubit-coupling map for a superconducting quantum device that hopes to act as a quantum router, and experimentally verify that optimizing the number of controlled-X gates decreases hardware errors that impact routing performance. Our results indicate that near-term realization of quantum routing using noisy superconducting quantum devices within real-world quantum networks is possible. Full article

We demonstrate that the non-Hermitian Hamiltonian approach can be used as a universal tool to design and describe a performance of single photon quantum electrodynamical circuits (cQED). As an example of the validity of this method, we calculate a novel six port quantum router, constructed from four qubits and three open waveguides. We have obtained analytical expressions, which describe the transmission and reflection coefficients of a single photon in general form taking into account the spread qubit’s parameters. We show that, due to naturally derived interferences, in situ tuning the probability of photon detection in desired ports. Full article

Optomechanics may be viewed as a light-mechanics interface to realize hybrid structures for (classical or quantum) information processing, switching or storage. Using the two-laser technique, in this paper, we theoretically devise a protocol for quantum light memory via a cavity optomechanical system composed of a Fabry–Perot cavity and a mechanical resonator. Due to the long-lived mechanical resonator, this quantum memory for light based on optomechanically induced transparency (OMIT) can serve as a long-term memory that can store the full quantum light contained in an optical pulse. It is shown that, with the tunable pump laser, the quantum signal light can be reaccelerated and converted back on demand. Our presented work could open the door to all-optical routers for light memory devices and have a guide to actual experiments. Full article