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

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.

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Efficient reversible quantum design of sig-magnitude to two's complement converters

Quantum Information and Computation ◽

10.26421/qic20.9-10-3 ◽

2020 ◽

Vol 20 (9&10) ◽

pp. 747-765

Author(s):

F. Orts ◽

G. Ortega ◽

E.M. E.M. Garzon

Keyword(s):

Quantum Computing ◽

Scientific Community ◽

Quantum Computer ◽

Fault Tolerant ◽

State Of The Art ◽

The Other ◽

Quantum Computers ◽

Binary Number ◽

Quantum Cost ◽

The One

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.

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Comparative Quality Estimation for Machine Translation Observations on Machine Learning and Features

Prague Bulletin of Mathematical Linguistics ◽

10.1515/pralin-2017-0029 ◽

2017 ◽

Vol 108 (1) ◽

pp. 307-318 ◽

Cited By ~ 1

Author(s):

Eleftherios Avramidis

Keyword(s):

Machine Learning ◽

Feature Selection ◽

Machine Translation ◽

State Of The Art ◽

Linear Method ◽

The State ◽

Quality Estimation ◽

Art Methods ◽

Improved Performance

AbstractA deeper analysis on Comparative Quality Estimation is presented by extending the state-of-the-art methods with adequacy and grammatical features from other Quality Estimation tasks. The previously used linear method, unable to cope with the augmented features, is replaced with a boosting classifier assisted by feature selection. The methods indicated show improved performance for 6 language pairs, when applied on the output from MT systems developed over 7 years. The improved models compete better with reference-aware metrics.Notable conclusions are reached through the examination of the contribution of the features in the models, whereas it is possible to identify common MT errors that are captured by the features. Many grammatical/fluency features have a good contribution, few adequacy features have some contribution, whereas source complexity features are of no use. The importance of many fluency and adequacy features is language-specific.

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Prospects for quantum computing: Extremely doubtful

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194514603573 ◽

2014 ◽

Vol 33 ◽

pp. 1460357 ◽

Cited By ~ 1

Author(s):

M. I. Dyakonov

Keyword(s):

Quantum Computing ◽

Large Scale ◽

Quantum Computer ◽

Chaotic Behavior ◽

Physical World ◽

The State ◽

Strongly Nonlinear ◽

Unitary Transformations ◽

Strongly Nonlinear System ◽

Limited Precision

The quantum computer is supposed to process information by applying unitary transformations to 2N complex amplitudes defining the state of N qubits. A useful machine needing N~103 or more, the number of continuous parameters describing the state of a quantum computer at any given moment is at least 21000 ~10300 which is much greater than the number of protons in the Universe. However, the theorists believe that the feasibility of large-scale quantum computing has been proved via the “threshold theorem”. Like for any theorem, the proof is based on a number of assumptions considered as axioms. However, in the physical world none of these assumptions can be fulfilled exactly. Any assumption can be only approached with some limited precision. So, the rather meaningless “error per qubit per gate” threshold must be supplemented by a list of the precisions with which all assumptions behind the threshold theorem should hold. Such a list still does not exist. The theory also seems to ignore the undesired free evolution of the quantum computer caused by the energy differences of quantum states entering any given superposition. Another important point is that the hypothetical quantum computer will be a system of 103 –106 qubits PLUS an extremely complex and monstrously sophisticated classical apparatus. This huge and strongly nonlinear system will generally exhibit instabilities and chaotic behavior.

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Demonstration of Bomb Detection Using the IBM Quantum Computer

10.20944/preprints201902.0232.v1 ◽

2019 ◽

Author(s):

Ankit Raj ◽

Barnali Das ◽

Bikash K. Behera ◽

Prasanta K. Panigrahi

Keyword(s):

Quantum Computing ◽

Quantum Computer ◽

Quantum Particle ◽

The State ◽

Copenhagen Interpretation ◽

Quantum Circuits ◽

Zehnder Interferometer ◽

Computer Designing ◽

Ibm Quantum Experience ◽

Interaction Free Measurement

According to Copenhagen interpretation, a quantum particle can exist in a superposition of all possible states, out of which only one state is observed when it is measured. Interestingly, it has been observed that interaction with the quantum particle during measurement can also affect the outcome of the state. A scheme for interaction free measurement was proposed by Elitzur and Vaidman [Found. Phys. 23, 987 (1993)], where they used Mach Zehnder interferometer to detect whether a bomb is alive or dead. In 25 % of the cases they were able to detect that the bomb is alive without exploding it. Here, we demonstrate the above experiment using quantum computing, which can be realized in a quantum computer designing quantum circuits on it. We explicate all the cases, including whether the bomb is alive or dead by proposing new quantum circuits and executing those in QISKit as provided by IBM Quantum Experience platform and verify the obtained results.

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Nearest centroid classification on a trapped ion quantum computer

npj Quantum Information ◽

10.1038/s41534-021-00456-5 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Sonika Johri ◽

Shantanu Debnath ◽

Avinash Mocherla ◽

Alexandros SINGK ◽

Anupam Prakash ◽

...

Keyword(s):

Machine Learning ◽

Quantum Computer ◽

State Of The Art ◽

Synthetic Data ◽

Quantum Computers ◽

Trapped Ion ◽

Quantum Machine Learning ◽

Real World Applications ◽

Promising Area ◽

Centroid Classifier

AbstractQuantum machine learning has seen considerable theoretical and practical developments in recent years and has become a promising area for finding real world applications of quantum computers. In pursuit of this goal, here we combine state-of-the-art algorithms and quantum hardware to provide an experimental demonstration of a quantum machine learning application with provable guarantees for its performance and efficiency. In particular, we design a quantum Nearest Centroid classifier, using techniques for efficiently loading classical data into quantum states and performing distance estimations, and experimentally demonstrate it on a 11-qubit trapped-ion quantum machine, matching the accuracy of classical nearest centroid classifiers for the MNIST handwritten digits dataset and achieving up to 100% accuracy for 8-dimensional synthetic data.

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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.

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