10,669 research outputs found
Revisiting Deniability in Quantum Key Exchange via Covert Communication and Entanglement Distillation
We revisit the notion of deniability in quantum key exchange (QKE), a topic
that remains largely unexplored. In the only work on this subject by Donald
Beaver, it is argued that QKE is not necessarily deniable due to an
eavesdropping attack that limits key equivocation. We provide more insight into
the nature of this attack and how it extends to other constructions such as QKE
obtained from uncloneable encryption. We then adopt the framework for quantum
authenticated key exchange, developed by Mosca et al., and extend it to
introduce the notion of coercer-deniable QKE, formalized in terms of the
indistinguishability of real and fake coercer views. Next, we apply results
from a recent work by Arrazola and Scarani on covert quantum communication to
establish a connection between covert QKE and deniability. We propose DC-QKE, a
simple deniable covert QKE protocol, and prove its deniability via a reduction
to the security of covert QKE. Finally, we consider how entanglement
distillation can be used to enable information-theoretically deniable protocols
for QKE and tasks beyond key exchange.Comment: 16 pages, published in the proceedings of NordSec 201
Efficient Online Quantum Generative Adversarial Learning Algorithms with Applications
The exploration of quantum algorithms that possess quantum advantages is a
central topic in quantum computation and quantum information processing. One
potential candidate in this area is quantum generative adversarial learning
(QuGAL), which conceptually has exponential advantages over classical
adversarial networks. However, the corresponding learning algorithm remains
obscured. In this paper, we propose the first quantum generative adversarial
learning algorithm-- the quantum multiplicative matrix weight algorithm
(QMMW)-- which enables the efficient processing of fundamental tasks. The
computational complexity of QMMW is polynomially proportional to the number of
training rounds and logarithmically proportional to the input size. The core
concept of the proposed algorithm combines QuGAL with online learning. We
exploit the implementation of QuGAL with parameterized quantum circuits, and
numerical experiments for the task of entanglement test for pure state are
provided to support our claims
Teaching Quantum Interpretations: Revisiting the goals and practices of introductory quantum physics courses
Most introductory quantum physics instructors would agree that transitioning
students from classical to quantum thinking is an important learning goal, but
may disagree on whether or how this can be accomplished. Although (and perhaps
because) physicists have long debated the physical interpretation of quantum
theory, many instructors choose to avoid emphasizing interpretive themes; or
they discuss the views of scientists in their classrooms, but do not adequately
attend to student interpretations. In this synthesis and extension of prior
work, we demonstrate: (1) instructors vary in their approaches to teaching
interpretive themes; (2) different instructional approaches have differential
impacts on student thinking; and (3) when student interpretations go
unattended, they often develop their own (sometimes scientifically undesirable)
views. We introduce here a new modern physics curriculum that explicitly
attends to student interpretations, and provide evidence-based arguments that
doing so helps them to develop more consistent interpretations of quantum
phenomena, more sophisticated views of uncertainty, and greater interest in
quantum physics.Comment: 14 pages, 11 figures; submitted to PRST-PER: Focused Collection on
Upper-Division PER. arXiv admin note: text overlap with arXiv:1409.849
Mind and Brain States
With neurons emergence, life alters itself in a remarkable way. This embodied neurons become carriers of signals, and processing devices: it begins an inexorable progression of functional complexity, from increasingly drawn behaviors to the mind and eventually to consciousness [Damasio, 2010]. In which moment has awareness arisen in the history of life? The emergence of human consciousness is associated with evolutionary developments in brain, behavior and mind, which ultimately lead to the creation of culture, a radical novelty in natural history. It is in this context of biological evolution of conscious brains that we raise the question: how conscious brains connect with each other? In order to answer it, I will explore how brain states and conscious states each participate in dynamic interactive processes involving the whole organism. I will argue that a possible way to overcome the hard problem of consciousness might be based on the notion of embodiment as a process of embedding the mental in the living organism relating dynamically with the environment through the sensorymotor experience. In order to do so, I will provide an assembly between an anthropologic perspective of consciousness with contemporary Philosophy of Mind, Interaction Theory [Gallagher 2001, 2008; Zahavi 2001, 2008; Fuchs and De Jaegher 2009]
Graduate Quantum Mechanics Reform
We address four main areas in which graduate quantum mechanics education can
be improved: course content, textbook, teaching methods, and assessment tools.
We report on a three year longitudinal study at the Colorado School of Mines
using innovations in all these areas. In particular, we have modified the
content of the course to reflect progress in the field in the last 50 years,
used textbooks that include such content, incorporated a variety of teaching
techniques based on physics education research, and used a variety of
assessment tools to study the effectiveness of these reforms. We present a new
assessment tool, the Graduate Quantum Mechanics Conceptual Survey, and further
testing of a previously developed assessment tool, the Quantum Mechanics
Conceptual Survey. We find that graduate students respond well to
research-based techniques that have been tested mainly in introductory courses,
and that they learn much of the new content introduced in each version of the
course. We also find that students' ability to answer conceptual questions
about graduate quantum mechanics is highly correlated with their ability to
solve calculational problems on the same topics. In contrast, we find that
students' understanding of basic undergraduate quantum mechanics concepts at
the modern physics level is not improved by instruction at the graduate level.Comment: accepted to American Journal of Physic
Quantum-optical influences in optoelectronics - an introduction
This focused review discusses the increasing importance of quantum optics in the physics and engineering of optoelectronic components. Two influences relating to cavity quantum electrodynamics are presented. One involves the development of low threshold lasers, when the channeling of spontaneous emission into the lasing mode becomes so efficient that the concept of lasing needs revisiting. The second involves the quieting of photon statistics to produce single-photon sources for applications such as quantum information processing. An experimental platform, consisting of quantum-dot gain media inside micro- and nanocavities, is used to illustrate these influences of the quantum mechanical aspect of radiation. An overview is also given on cavity quantum electrodynamics models that may be applied to analyze experiments or design devices.EC/FP7/615613/EU/External Quantum Control of Photonic Semiconductor Nanostructures/EXQUISIT
Langevin Simulations of a Long Range Electron Phonon Model
We present a Quantum Monte Carlo (QMC) study, based on the Langevin equation,
of a Hamiltonian describing electrons coupled to phonon degrees of freedom. The
bosonic part of the action helps control the variation of the field in
imaginary time. As a consequence, the iterative conjugate gradient solution of
the fermionic action, which depends on the boson coordinates, converges more
rapidly than in the case of electron-electron interactions, such as the Hubbard
Hamiltonian. Fourier Acceleration is shown to be a crucial ingredient in
reducing the equilibration and autocorrelation times. After describing and
benchmarking the method, we present results for the phase diagram focusing on
the range of the electron-phonon interaction. We delineate the regions of
charge density wave formation from those in which the fermion density is
inhomogeneous, caused by phase separation. We show that the Langevin approach
is more efficient than the Determinant QMC method for lattice sizes and that it therefore opens a potential path to problems including,
for example, charge order in the 3D Holstein model
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