7,052 research outputs found
Fault Models for Quantum Mechanical Switching Networks
The difference between faults and errors is that, unlike faults, errors can
be corrected using control codes. In classical test and verification one
develops a test set separating a correct circuit from a circuit containing any
considered fault. Classical faults are modelled at the logical level by fault
models that act on classical states. The stuck fault model, thought of as a
lead connected to a power rail or to a ground, is most typically considered. A
classical test set complete for the stuck fault model propagates both binary
basis states, 0 and 1, through all nodes in a network and is known to detect
many physical faults. A classical test set complete for the stuck fault model
allows all circuit nodes to be completely tested and verifies the function of
many gates. It is natural to ask if one may adapt any of the known classical
methods to test quantum circuits. Of course, classical fault models do not
capture all the logical failures found in quantum circuits. The first obstacle
faced when using methods from classical test is developing a set of realistic
quantum-logical fault models. Developing fault models to abstract the test
problem away from the device level motivated our study. Several results are
established. First, we describe typical modes of failure present in the
physical design of quantum circuits. From this we develop fault models for
quantum binary circuits that enable testing at the logical level. The
application of these fault models is shown by adapting the classical test set
generation technique known as constructing a fault table to generate quantum
test sets. A test set developed using this method is shown to detect each of
the considered faults.Comment: (almost) Forgotten rewrite from 200
Fault testing quantum switching circuits
Test pattern generation is an electronic design automation tool that attempts
to find an input (or test) sequence that, when applied to a digital circuit,
enables one to distinguish between the correct circuit behavior and the faulty
behavior caused by particular faults. The effectiveness of this classical
method is measured by the fault coverage achieved for the fault model and the
number of generated vectors, which should be directly proportional to test
application time. This work address the quantum process validation problem by
considering the quantum mechanical adaptation of test pattern generation
methods used to test classical circuits. We found that quantum mechanics allows
one to execute multiple test vectors concurrently, making each gate realized in
the process act on a complete set of characteristic states in space/time
complexity that breaks classical testability lower bounds.Comment: (almost) Forgotten rewrite from 200
Error-power tradeoffs in QCA design
In this work we present an error-power tradeoff study in a Quantum-dot Cellular Automata (QCA) circuit design. Device parameter variation to optimize performance is a very crucial step in the development of a technology. In this work we vary the maximum kink energy of a QCA circuit to perform an error-power tradeoff study in QCA design. We make use of graphical probabilistic models to estimate polarization errors and non-adiabatic energy dissipated in a clocked QCA circuit and demonstrate the tradeoff studies on the basic QCA circuits such as majority gate and inverter. We also show how this study can be used by comparing two single bit adder designs. The study will be of great use to designers and fabrication scientists to choose the most optimum size and spacing of QCA cells to fabricate QCA logic designs
Unconditional measurement-based quantum computation with optomechanical continuous variables
Universal quantum computation encoded over continuous variables can be
achieved via Gaussian measurements acting on entangled non-Gaussian states.
However, due to the weakness of available nonlinearities, generally these
states can only be prepared conditionally, potentially with low probability.
Here we show how universal quantum computation could be implemented
unconditionally using an integrated platform able to sustain both linear and
quadratic optomechanical-like interactions. Specifically, considering cavity
opto- and electro-mechanical systems, we propose a realisation of a
driven-dissipative dynamics that deterministically prepares the required
non-Gaussian cluster states --- entangled squeezed states of multiple
mechanical oscillators suitably interspersed with cubic-phase states. We next
demonstrate how arbitrary Gaussian measurements on the cluster nodes can be
performed by continuously monitoring the output cavity field. Finally, the
feasibility requirements of this approach are analysed in detail, suggesting
that its building blocks are within reach of current technology.Comment: 5 pages + 9 pages supplementary materia
From Quantum Optics to Quantum Technologies
Quantum optics is the study of the intrinsically quantum properties of light.
During the second part of the 20th century experimental and theoretical
progress developed together; nowadays quantum optics provides a testbed of many
fundamental aspects of quantum mechanics such as coherence and quantum
entanglement. Quantum optics helped trigger, both directly and indirectly, the
birth of quantum technologies, whose aim is to harness non-classical quantum
effects in applications from quantum key distribution to quantum computing.
Quantum light remains at the heart of many of the most promising and
potentially transformative quantum technologies. In this review, we celebrate
the work of Sir Peter Knight and present an overview of the development of
quantum optics and its impact on quantum technologies research. We describe the
core theoretical tools developed to express and study the quantum properties of
light, the key experimental approaches used to control, manipulate and measure
such properties and their application in quantum simulation, and quantum
computing.Comment: 20 pages, 3 figures, Accepted, Prog. Quant. Ele
Towards Structural Testing of Superconductor Electronics
Many of the semiconductor technologies are already\ud
facing limitations while new-generation data and\ud
telecommunication systems are implemented. Although in\ud
its infancy, superconductor electronics (SCE) is capable of\ud
handling some of these high-end tasks. We have started a\ud
defect-oriented test methodology for SCE, so that reliable\ud
systems can be implemented in this technology. In this\ud
paper, the details of the study on the Rapid Single-Flux\ud
Quantum (RSFQ) process are presented. We present\ud
common defects in the SCE processes and corresponding\ud
test methodologies to detect them. The (measurement)\ud
results prove that we are able to detect possible random\ud
defects for statistical purposes in yield analysis. This\ud
paper also presents possible test methodologies for RSFQ\ud
circuits based on defect oriented testing (DOT)
Synthesis and Optimization of Reversible Circuits - A Survey
Reversible logic circuits have been historically motivated by theoretical
research in low-power electronics as well as practical improvement of
bit-manipulation transforms in cryptography and computer graphics. Recently,
reversible circuits have attracted interest as components of quantum
algorithms, as well as in photonic and nano-computing technologies where some
switching devices offer no signal gain. Research in generating reversible logic
distinguishes between circuit synthesis, post-synthesis optimization, and
technology mapping. In this survey, we review algorithmic paradigms ---
search-based, cycle-based, transformation-based, and BDD-based --- as well as
specific algorithms for reversible synthesis, both exact and heuristic. We
conclude the survey by outlining key open challenges in synthesis of reversible
and quantum logic, as well as most common misconceptions.Comment: 34 pages, 15 figures, 2 table
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