State of the Art and Prospects for Quantum Computing

Despite the great interest that the scientific community has in quantum computing, the scarcity and high cost of resources prevent to advance in this field. Specifically, qubits are very expensive to build, causing the few available quantum computers are tremendously limited in their number of qubits and delaying their progress. This work presents new reversible circuits that optimize the necessary resources for the conversion of a sign binary number into two's complement of N digits. The benefits of our work are two: on the one hand, the proposed two's complement converters are fault tolerant circuits and also are more efficient in terms of resources (essentially, quantum cost, number of qubits, and T-count) than the described in the literature. On the other hand, valuable information about available converters and, what is more, quantum adders, is summarized in tables for interested researchers. The converters have been measured using robust metrics and have been compared with the state-of-the-art circuits. The code to build them in a real quantum computer is given.

Download Full-text

Gaussian Elimination versus Greedy Methods for the Synthesis of Linear Reversible Circuits

ACM Transactions on Quantum Computing ◽

10.1145/3474226 ◽

2021 ◽

Vol 2 (3) ◽

pp. 1-26

Author(s):

Timothée Goubault De Brugière ◽

Marc Baboulin ◽

Benoît Valiron ◽

Simon Martiel ◽

Cyril Allouche

Keyword(s):

Quantum Computing ◽

State Of The Art ◽

Gaussian Elimination ◽

Random Operators ◽

Lu Factorization ◽

Large Problem ◽

Computational Costs ◽

Elimination Algorithm ◽

Reversible Circuits ◽

Greedy Methods

Linear reversible circuits represent a subclass of reversible circuits with many applications in quantum computing. These circuits can be efficiently simulated by classical computers and their size is polynomially bounded by the number of qubits, making them a good candidate to deploy efficient methods to reduce computational costs. We propose a new algorithm for synthesizing any linear reversible operator by using an optimized version of the Gaussian elimination algorithm coupled with a tuned LU factorization. We also improve the scalability of purely greedy methods. Overall, on random operators, our algorithms improve the state-of-the-art methods for specific ranges of problem sizes: The custom Gaussian elimination algorithm provides the best results for large problem sizes (n > 150), while the purely greedy methods provide quasi optimal results when n < 30. On a benchmark of reversible functions, we manage to significantly reduce the CNOT count and the depth of the circuit while keeping other metrics of importance (T-count, T-depth) as low as possible.

Download Full-text

A Quantum Approach Using Stochastic Simulation and Schrodinger with Multi-Layer Learning for Finding Features from Dataset

Journal of Computational and Theoretical Nanoscience ◽

10.1166/jctn.2020.8923 ◽

2020 ◽

Vol 17 (6) ◽

pp. 2514-2518

Author(s):

Kapil Prashar ◽

Rajneesh Talwar ◽

Chander Kant

Keyword(s):

Quantum Computing ◽

Mathematical Models ◽

Stochastic Simulation ◽

Statistical Models ◽

State Of The Art ◽

Research Work ◽

Current Approach ◽

Suggested Model ◽

Quantum Approach ◽

Multiple State

Quantum computing relies on the quantity of the mechanical phenomenon, such as interference and overlap. It aims to solve issues which are not realistically possible on computers. The research work introduces the new quantum-based model from a provided dataset for forecasting the infection. This technique is beneficial in describing the association among different statistical models. Our study has resulted in highest precision than ever applied technique, which was differentiated and calculated from the defined dataset and results. Such suggested strategies were evaluated and reviewed against multiple state-of-the-art methods to demonstrate efficacy. The qualitative and graphical results are provided for the verification of the current approach. The suggested model is more robust than existing mathematical models due to the findings.

Download Full-text

Power-optimal, stabilized entangling gate between trapped-ion qubits

npj Quantum Information ◽

10.1038/s41534-021-00489-w ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Reinhold Blümel ◽

Nikodem Grzesiak ◽

Neal Pisenti ◽

Kenneth Wright ◽

Yunseong Nam

Keyword(s):

Quantum Computing ◽

Parameter Space ◽

Arbitrary Order ◽

Quantum Computer ◽

State Of The Art ◽

Linear Method ◽

The State ◽

External Parameter ◽

Trapped Ion

AbstractTo achieve scalable quantum computing, improving entangling-gate fidelity and its implementation efficiency are of utmost importance. We present here a linear method to construct provably power-optimal entangling gates on an arbitrary pair of qubits on a trapped-ion quantum computer. This method leverages simultaneous modulation of amplitude, frequency, and phase of the beams that illuminate the ions and, unlike the state of the art, does not require any search in the parameter space. The linear method is extensible, enabling stabilization against external parameter fluctuations to an arbitrary order at a cost linear in the order. We implement and demonstrate the power-optimal, stabilized gate on a trapped-ion quantum computer.

Download Full-text

State-of-the-art quantum computing simulators: Features, optimizations, and improvements for D-GM

Neurocomputing ◽

10.1016/j.neucom.2019.01.118 ◽

2020 ◽

Vol 393 ◽

pp. 223-233 ◽

Cited By ~ 1

Author(s):

A.B. de Avila ◽

R.H.S. Reiser ◽

M.L. Pilla ◽

A.C. Yamin

Keyword(s):

Quantum Computing ◽

State Of The Art

Download Full-text

An Adaptive Optimizer for Measurement-Frugal Variational Algorithms

Quantum ◽

10.22331/q-2020-05-11-263 ◽

2020 ◽

Vol 4 ◽

pp. 263 ◽

Cited By ~ 6

Author(s):

Jonas M. Kübler ◽

Andrew Arrasmith ◽

Lukasz Cincio ◽

Patrick J. Coles

Keyword(s):

Quantum Computing ◽

Partial Derivative ◽

Gradient Descent ◽

State Of The Art ◽

Stochastic Gradient ◽

Stochastic Gradient Descent ◽

Near Term ◽

Variational Algorithms

Variational hybrid quantum-classical algorithms (VHQCAs) have the potential to be useful in the era of near-term quantum computing. However, recently there has been concern regarding the number of measurements needed for convergence of VHQCAs. Here, we address this concern by investigating the classical optimizer in VHQCAs. We introduce a novel optimizer called individual Coupled Adaptive Number of Shots (iCANS). This adaptive optimizer frugally selects the number of measurements (i.e., number of shots) both for a given iteration and for a given partial derivative in a stochastic gradient descent. We numerically simulate the performance of iCANS for the variational quantum eigensolver and for variational quantum compiling, with and without noise. In all cases, and especially in the noisy case, iCANS tends to out-perform state-of-the-art optimizers for VHQCAs. We therefore believe this adaptive optimizer will be useful for realistic VHQCA implementations, where the number of measurements is limited.

Download Full-text

Ytterbium ion trap quantum computing: The current state-of-the-art

AVS Quantum Science ◽

10.1116/5.0065951 ◽

2021 ◽

Vol 3 (4) ◽

pp. 044101

Author(s):

Gavin N. Nop ◽

Durga Paudyal ◽

Jonathan D. H. Smith

Keyword(s):

Quantum Computing ◽

Ion Trap ◽

State Of The Art ◽

Current State ◽

Ytterbium Ion

Download Full-text

Practical Picture Processing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051700 ◽

1974 ◽

Vol 32 ◽

pp. 338-339

Author(s):

T. A. Welton

Keyword(s):

Radiation Damage ◽

Coherence Length ◽

Spatial Information ◽

State Of The Art ◽

Coherent Radiation ◽

The State ◽

Energy Spread ◽

Electron Micrograph ◽

Picture Processing ◽

Molecular Skeleton

Various authors have emphasized the spatial information resident in an electron micrograph taken with adequately coherent radiation. In view of the completion of at least one such instrument, this opportunity is taken to summarize the state of the art of processing such micrographs. We use the usual symbols for the aberration coefficients, and supplement these with £ and 6 for the transverse coherence length and the fractional energy spread respectively. He also assume a weak, biologically interesting sample, with principal interest lying in the molecular skeleton remaining after obvious hydrogen loss and other radiation damage has occurred.

Download Full-text

A Macintosh Interface for the Cameca Camebax-Micro Electron Microprobe

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010018094x ◽

1990 ◽

Vol 48 (1) ◽

pp. 438-439

Author(s):

Carl E. Henderson

Keyword(s):

Electron Microprobe ◽

Processing Speed ◽

Word Processing ◽

State Of The Art ◽

Computer Control ◽

Third Party ◽

Disk Storage ◽

The Past ◽

User Facility ◽

Instrument Control

Over the past few years it has become apparent in our multi-user facility that the computer system and software supplied in 1985 with our CAMECA CAMEBAX-MICRO electron microprobe analyzer has the greatest potential for improvement and updating of any component of the instrument. While the standard CAMECA software running on a DEC PDP-11/23+ computer under the RSX-11M operating system can perform almost any task required of the instrument, the commands are not always intuitive and can be difficult to remember for the casual user (of which our laboratory has many). Given the widespread and growing use of other microcomputers (such as PC’s and Macintoshes) by users of the microprobe, the PDP has become the “oddball” and has also fallen behind the state-of-the-art in terms of processing speed and disk storage capabilities. Upgrade paths within products available from DEC are considered to be too expensive for the benefits received. After using a Macintosh for other tasks in the laboratory, such as instrument use and billing records, word processing, and graphics display, its unique and “friendly” user interface suggested an easier-to-use system for computer control of the electron microprobe automation. Specifically a Macintosh IIx was chosen for its capacity for third-party add-on cards used in instrument control.

Download Full-text