Generation and sampling of quantum states of light in a silicon chip

Implementing large instances of quantum algorithms requires the processing of many quantum information carriers in a hardware platform that supports the integration of different components. While established semiconductor fabrication processes can integrate many photonic components, the generation and algorithmic processing of many photons has been a bottleneck in integrated photonics. Here we report the on-chip generation and processing of quantum states of light with up to eight photons in quantum sampling algorithms. Switching between different optical pumping regimes, we implement the Scattershot, Gaussian and standard boson sampling protocols in the same silicon chip, which integrates linear and nonlinear photonic circuitry. We use these results to benchmark a quantum algorithm for calculating molecular vibronic spectra. Our techniques can be readily scaled for the on-chip implementation of specialised quantum algorithms with tens of photons, pointing the way to efficiency advantages over conventional computers

Current advances in~information quantum technologies - critical issues

This article reviews chosen topics related to the development of Information Quantum Technologies in the major areas of measurements, communications, and computing. These fields start to build their ecosystems which in the future will probably coalesce into a homogeneous quantum information layer consisting of such interconnected components as quantum internet, full size quantum computers with efficient error corrections and ultrasensitive quantum metrology nodes stationary and mobile. Today, however, the skepticism expressing many doubts about the realizability of this optimistic view fights with a cheap optimism pouring out of some popular press releases. Where is the truth? Financing of the IQT by key players in research, development and markets substantially strengthens the optimistic side. Keeping the bright side with some reservations, we concentrate on showing the FAST pace of IQT developments in such areas as biological sciences, quantum evolutionary computations, quantum internet and some of its components

Cracking the Quantum Advantage threshold for Gaussian Boson Sampling

Scientists in quantum technology aspire to quantum advantage: a computational result unattainable with classical computers. Gaussian boson sampling experiment has been already claimed to achieve this goal. In this setup squeezed light states interfere in a mid-sized linear optical network. The exact simulation of the counting statistics of $n$ detectors is far beyond the possibilities of modern supercomputers once $n$ exceeds $50$. We challenge quantum advantage for a mid-sized Gaussian boson sampling setup and propose the approximate algorithm to obtain the probability of any specific measurement outcome. For an idealized 70-mode device, our approximation achieves accuracy competitive with the experimental one.Comment: The supplementary material is uploaded as a separate fil

A bibliography on parallel and vector numerical algorithms

This is a bibliography of numerical methods. It also includes a number of other references on machine architecture, programming language, and other topics of interest to scientific computing. Certain conference proceedings and anthologies which have been published in book form are listed also

Hyper-Sensitive MEMS Pressure Sensor Array for Microscale Bubble Pressure Measurement

As technology is advancing, more complex, efficient, and powerful devices are being made. These powerful devices generate a lot of heat which needs to be taken out to maximize their performance. Hence, efforts are being made to improve cooling techniques for these devices. Boiling is one such technique used in the cooling of devices. The heat transfer performance in the flow boiling systems is higher than that in pool boiling systems. With a simple add-on tapered manifold over a plain surface, we can convert pool boiling to flow boiling. This study will lead to improved performance and reliability of microelectronic devices, supercomputers, server chips, etc. The forces from bubbles growing can provide a pumpless, self-sustained unidirectional flow effectively transforming pool boiling into the extremely efficient flow boiling, resulting in energy savings. MEMS pressure sensor array will be mounted at the end of tapered manifold to map the pressure field around a nucleating bubble. The thesis describes the design, fabrication, packaging, and testing of a bulk micromachined sensor array that is capable of monitoring the pressure progression of a bubble. The sensor utilizes an extremely thin 225 nm square Si3N4 diaphragm which is produced by etching away the bulk silicon with XeF2 through holes present in the diaphragm. A unique process flow was developed to achieve the diaphragm thickness in nanometers. Four polysilicon piezoresistors, mounted on the surface of the diaphragm, where the stress is maximum, are used by the sensor. The thesis also discusses the results obtained from the response of the fabricated sensor. Various attempts were made to get a voltage output in response to applied pressure. These values were acquired over a number of experiments repeated at similar experimental conditions to demonstrate the repeatability of the calibration data. The value of sensitivity, derived from the slope of the linear calibration plot of Vout (V) vs. Pressure (Pa), is 5.26 μV/Pa, which is very close to the required target hyper-sensitivity of 5 μV/Pa

Cell mechanics in flow: algorithms and applications

The computer simulations are pervasively used to improve the knowledge about biophysical phenomena and to quantify effects which are difficult to study experimentally. Generally, the numerical methods and models are desired to be as accurate as possible on the chosen length and time scales, but, at the same time, affordable in terms of computations. Until recently, the cell mechanics and blood flow phenomena on the sub-micron resolution could not be rigorously studied using computer simulations. However, within the last decade, advances in methods and hardware catalyzed the development of models for cells mechanics and blood flow modeling which, previously, were considered to be not feasible. In this context, a model should accurately describe a phenomenon, be computationally affordable, and be flexible to be applied to study different biophysical changes. This thesis focuses on the development of the new methods, models, and high-performance software implementation that expand the class of problems which can be studied numerically using particle-based methods. Microvascular networks have complex geometry, often without any symmetry, and to study them we need to tackle computational domains with several inlets and outlets. However, an absence of appropriate boundary conditions for particle- based methods hampers study of the blood flow in these domains. Another obstacle to model complex blood flow problems is the absence the highperformance software. This problem restricts the applicability of the of particlebased cell flow models to relatively small systems. Although there are several validated red blood cell models, to date, there are no models for suspended eukaryotic cells. The present thesis addresses these issues. We introduce new open boundary conditions for particle-based systems and apply them to study blood flow in a part of a microvascular network. We develop a software demonstrating outstanding performance on the largest supercomputers and used it to study blood flow in microfluidic devices. Finally, we present a new eukaryotic cell model which helps in quantifying the effect of sub-cellular components on the cell mechanics during deformations in microfluidic devices