10,219 research outputs found
Apollo command module mockup flammability tests
Apollo command module mockup flammability tests using three different atmosphere
Optimized Compilation of Aggregated Instructions for Realistic Quantum Computers
Recent developments in engineering and algorithms have made real-world
applications in quantum computing possible in the near future. Existing quantum
programming languages and compilers use a quantum assembly language composed of
1- and 2-qubit (quantum bit) gates. Quantum compiler frameworks translate this
quantum assembly to electric signals (called control pulses) that implement the
specified computation on specific physical devices. However, there is a
mismatch between the operations defined by the 1- and 2-qubit logical ISA and
their underlying physical implementation, so the current practice of directly
translating logical instructions into control pulses results in inefficient,
high-latency programs. To address this inefficiency, we propose a universal
quantum compilation methodology that aggregates multiple logical operations
into larger units that manipulate up to 10 qubits at a time. Our methodology
then optimizes these aggregates by (1) finding commutative intermediate
operations that result in more efficient schedules and (2) creating custom
control pulses optimized for the aggregate (instead of individual 1- and
2-qubit operations). Compared to the standard gate-based compilation, the
proposed approach realizes a deeper vertical integration of high-level quantum
software and low-level, physical quantum hardware. We evaluate our approach on
important near-term quantum applications on simulations of superconducting
quantum architectures. Our proposed approach provides a mean speedup of
, with a maximum of . Because latency directly affects the
feasibility of quantum computation, our results not only improve performance
but also have the potential to enable quantum computation sooner than otherwise
possible.Comment: 13 pages, to apper in ASPLO
Rescuing Complementarity With Little Drama
The AMPS paradox challenges black hole complementarity by apparently
constructing a way for an observer to bring information from the outside of the
black hole into its interior if there is no drama at its horizon, making
manifest a violation of monogamy of entanglement. We propose a new resolution
to the paradox: this violation cannot be explicitly checked by an infalling
observer in the finite proper time they have to live after crossing the
horizon. Our resolution depends on a weak relaxation of the no-drama condition
(we call it "little drama") which is the "complementarity dual" of scrambling
of information on the stretched horizon. When translated to the description of
the black hole interior, this implies that the fine-grained quantum information
of infalling matter is rapidly diffused across the entire interior while
classical observables and coarse-grained geometry remain unaffected. Under the
assumption that information has diffused throughout the interior, we consider
the difficulty of the information-theoretic task that an observer must perform
after crossing the event horizon of a Schwarzschild black hole in order to
verify a violation of monogamy of entanglement. We find that the time required
to complete a necessary subroutine of this task, namely the decoding of Bell
pairs from the interior and the late radiation, takes longer than the maximum
amount of time that an observer can spend inside the black hole before hitting
the singularity. Therefore, an infalling observer cannot observe monogamy
violation before encountering the singularity.Comment: 26 pages, 3 figures - v2: added references, small tweaks - v3:
corrected typos to reflect final published versio
Interface groups and financial transfer architectures
Analytic execution architectures have been proposed by the same authors as a
means to conceptualize the cooperation between heterogeneous collectives of
components such as programs, threads, states and services. Interface groups
have been proposed as a means to formalize interface information concerning
analytic execution architectures. These concepts are adapted to organization
architectures with a focus on financial transfers. Interface groups (and
monoids) now provide a technique to combine interface elements into interfaces
with the flexibility to distinguish between directions of flow dependent on
entity naming.
The main principle exploiting interface groups is that when composing a
closed system of a collection of interacting components, the sum of their
interfaces must vanish in the interface group modulo reflection. This certainly
matters for financial transfer interfaces.
As an example of this, we specify an interface group and within it some
specific interfaces concerning the financial transfer architecture for a part
of our local academic organization.
Financial transfer interface groups arise as a special case of more general
service architecture interfaces.Comment: 22 page
Impact Assessment of Hypothesized Cyberattacks on Interconnected Bulk Power Systems
The first-ever Ukraine cyberattack on power grid has proven its devastation
by hacking into their critical cyber assets. With administrative privileges
accessing substation networks/local control centers, one intelligent way of
coordinated cyberattacks is to execute a series of disruptive switching
executions on multiple substations using compromised supervisory control and
data acquisition (SCADA) systems. These actions can cause significant impacts
to an interconnected power grid. Unlike the previous power blackouts, such
high-impact initiating events can aggravate operating conditions, initiating
instability that may lead to system-wide cascading failure. A systemic
evaluation of "nightmare" scenarios is highly desirable for asset owners to
manage and prioritize the maintenance and investment in protecting their
cyberinfrastructure. This survey paper is a conceptual expansion of real-time
monitoring, anomaly detection, impact analyses, and mitigation (RAIM) framework
that emphasizes on the resulting impacts, both on steady-state and dynamic
aspects of power system stability. Hypothetically, we associate the
combinatorial analyses of steady state on substations/components outages and
dynamics of the sequential switching orders as part of the permutation. The
expanded framework includes (1) critical/noncritical combination verification,
(2) cascade confirmation, and (3) combination re-evaluation. This paper ends
with a discussion of the open issues for metrics and future design pertaining
the impact quantification of cyber-related contingencies
Simulation of nanostructure-based high-efficiency solar cells: challenges, existing approaches and future directions
Many advanced concepts for high-efficiency photovoltaic devices exploit the
peculiar optoelectronic properties of semiconductor nanostructures such as
quantum wells, wires and dots. While the optics of such devices is only
modestly affected due to the small size of the structures, the optical
transitions and electronic transport can strongly deviate from the simple bulk
picture known from conventional solar cell devices. This review article
discusses the challenges for an adequate theoretical description of the
photovoltaic device operation arising from the introduction of nanostructure
absorber and/or conductor components and gives an overview of existing device
simulation approaches.Comment: Invited paper, accepted for publication in IEEE Journal of Selected
Topics in Quantum Electronic
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