38 research outputs found
A Programmable True Random Number Generator Using Commercial Quantum Computers
Random number generators (RNG) are essential elements in many cryptographic
systems. True random number generators (TRNG) rely upon sources of randomness
from natural processes such as those arising from quantum mechanics phenomena.
We demonstrate that a quantum computer can serve as a high-quality, weakly
random source for a generalized user-defined probability mass function (PMF).
Specifically, QC measurement implements the process of variate sampling
according to a user-specified PMF resulting in a word comprised of electronic
bits that can then be processed by an extractor function to address
inaccuracies due to non-ideal quantum gate operations and other system biases.
We introduce an automated and flexible method for implementing a TRNG as a
programmed quantum circuit that executes on commercially-available, gate-model
quantum computers. The user specifies the desired word size as the number of
qubits and a definition of the desired PMF. Based upon the user specification
of the PMF, our compilation tool automatically synthesizes the desired TRNG as
a structural OpenQASM file containing native gate operations that are optimized
to reduce the circuit's quantum depth. The resulting TRNG provides multiple
bits of randomness for each execution/measurement cycle; thus, the number of
random bits produced in each execution is limited only by the size of the QC.
We provide experimental results to illustrate the viability of this approach.Comment: 15 pages, 7 figures, SPIE Defense + Commercial Sensing: Quantum
Information Science, Sensing, and Computation X
Automated Quantum Oracle Synthesis with a Minimal Number of Qubits
Several prominent quantum computing algorithms--including Grover's search
algorithm and Shor's algorithm for finding the prime factorization of an
integer--employ subcircuits termed 'oracles' that embed a specific instance of
a mathematical function into a corresponding bijective function that is then
realized as a quantum circuit representation. Designing oracles, and
particularly, designing them to be optimized for a particular use case, can be
a non-trivial task. For example, the challenge of implementing quantum circuits
in the current era of NISQ-based quantum computers generally dictates that they
should be designed with a minimal number of qubits, as larger qubit counts
increase the likelihood that computations will fail due to one or more of the
qubits decohering. However, some quantum circuits require that function domain
values be preserved, which can preclude using the minimal number of qubits in
the oracle circuit. Thus, quantum oracles must be designed with a particular
application in mind. In this work, we present two methods for automatic quantum
oracle synthesis. One of these methods uses a minimal number of qubits, while
the other preserves the function domain values while also minimizing the
overall required number of qubits. For each method, we describe known quantum
circuit use cases, and illustrate implementation using an automated quantum
compilation and optimization tool to synthesize oracles for a set of benchmark
functions; we can then compare the methods with metrics including required
qubit count and quantum circuit complexity.Comment: 18 pages, 10 figures, SPIE Defense + Commercial Sensing: Quantum
Information Science, Sensing, and Computation X
Automated Synthesis of Quantum Subcircuits
The quantum computer has become contemporary reality, with the first
two-qubit machine of mere decades ago transforming into cloud-accessible
devices with tens, hundreds, or--in a few cases--even thousands of qubits.
While such hardware is noisy and still relatively small, the increasing number
of operable qubits raises another challenge: how to develop the now-sizeable
quantum circuits executable on these machines. Preparing circuits manually for
specifications of any meaningful size is at best tedious and at worst
impossible, creating a need for automation. This article describes an automated
quantum-software toolkit for synthesis, compilation, and optimization, which
transforms classically-specified, irreversible functions to both
technology-independent and technology-dependent quantum circuits. We also
describe and analyze the toolkit's application to three situations--quantum
read-only memories, quantum random number generators, and quantum oracles--and
illustrate the toolkit's start-to-finish features from the input of classical
functions to the output of quantum circuits ready-to-run on commercial
hardware. Furthermore, we illustrate how the toolkit enables research beyond
circuit synthesis, including comparison of synthesis and optimization methods
and deeper understanding of even well-studied quantum algorithms. As quantum
hardware continues to develop, such quantum circuit toolkits will play a
critical role in realizing its potential.Comment: 49 pages, 25 figures, 20 table
A comparison of respondent-driven and venue-based sampling of female sex workers in Liuzhou, China
ObjectivesTo compare two methods for sampling female sex workers (FSWs) for bio-behavioural surveillance. We compared the populations of sex workers recruited by the venue-based Priorities for Local AIDS Control Efforts (PLACE) method and a concurrently implemented network-based sampling method, respondent-driven sampling (RDS), in Liuzhou, China.MethodsFor the PLACE protocol, all female workers at a stratified random sample of venues identified as places where people meet new sexual partners were interviewed and tested for syphilis. Female workers who reported sex work in the past 4â
weeks were categorised as FSWs. RDS used peer recruitment and chain referral to obtain a sample of FSWs. Data were collected between October 2009 and January 2010. We compared the socio-demographic characteristics and the percentage with a positive syphilis test of FSWs recruited by PLACE and RDS.ResultsThe prevalence of a positive syphilis test was 24% among FSWs recruited by PLACE and 8.5% among those recruited by RDS and tested (prevalence ratio 3.3; 95% CI 1.5 to 7.2). Socio-demographic characteristics (age, residence and monthly income) also varied by sampling method. PLACE recruited fewer FSWs than RDS (161 vs 583), was more labour-intensive and had difficulty gaining access to some venues. RDS was more likely to recruit from areas near the RDS office and from large low prevalence entertainment venues.ConclusionsSurveillance protocols using different sampling methods can obtain different estimates of prevalence and population characteristics. Venue-based and network-based methods each have strengths and limitations reflecting differences in design and assumptions. We recommend that more research be conducted on measuring bias in bio-behavioural surveillance
Habits of Mind: Designing Courses for Student Success
Although content knowledge remains at the heart of college teaching and learning, forward-thinking instructors recognize that we must also provide 21st-century college students with transferable skills (sometimes called portable intellectual abilities) to prepare them for their futures (Vazquez, 2020; Ritchhart, 2015; Venezia & Jaeger, 2013; Hazard, 2012). To âgrow their capacity as efficacious thinkers to navigate and thrive in the face of unprecedented changeâ (Costa et al., 2023), students must learn and improve important study skills and academic dispositions throughout their educational careers. If we do not focus on skills-building in college courses, students will not be prepared for the challenges that await them after they leave institutions of higher education. If students are not prepared for these postsecondary education challenges, then it is fair to say that college faculty have failed them
Reverberation mapping of optical emission lines in five active galaxies
For a video summarizing the main results, see https://www.youtube.com/watch?v=KaC-jPsIY0QWe present the first results from an optical reverberation mapping campaign executed in 2014 targeting the active galactic nuclei (AGNs) MCG+08-11-011, NGC 2617, NGC 4051, 3C 382, and Mrk 374. Our targets have diverse and interesting observational properties, including a "changing look" AGN and a broad-line radio galaxy. Based on continuum-HÎČ lags, we measure black hole masses for all five targets. We also obtain HÎł and He ii λ4686 lags for all objects except 3C 382. The He ii λ4686 lags indicate radial stratification of the BLR, and the masses derived from different emission lines are in general agreement. The relative responsivities of these lines are also in qualitative agreement with photoionization models. These spectra have extremely high signal-to-noise ratios (100â300 per pixel) and there are excellent prospects for obtaining velocity-resolved reverberation signatures.Publisher PDFPeer reviewe
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Reading comprehension in autism spectrum disorders: The role of oral language and social functioning
Reading comprehension is an area of difficulty for many individuals with autism spectrum disorders (ASD). According to the Simple View of Reading, word recognition and oral language are both important determinants of reading comprehension ability. We provide a novel test of this model in 100 adolescents with ASD of varying intellectual ability. Further, we explore whether reading comprehension is additionally influenced by individual differences in social behaviour and social cognition in ASD. Adolescents with ASD aged 14-16 years completed assessments indexing word recognition, oral language, reading comprehension, social behaviour and social cognition. Regression analyses show that both word recognition and oral language explain unique variance in reading comprehension. Further, measures of social behaviour and social cognition predict reading comprehension after controlling for the variance explained by word recognition and oral language. This indicates that word recognition, oral language and social impairments may constrain reading comprehension in ASD
Inshore and offshore marine migration pathways of Atlantic salmon post-smolts from multiple rivers in Scotland, England, Northern Ireland and Ireland
The migratory behavior of Atlantic salmon (Salmo salar) post-smolts in coastal waters is poorly understood. In this collaborative study, 1914 smolts, from 25 rivers, in four countries were tagged with acoustic transmitters during a single seasonal migration. In total, 1105 post-smolts entered the marine study areas and 438 (39.6%) were detected on a network of 414 marine acoustic receivers and an autonomous underwater vehicle. Migration pathways (defined as the shortest distance between two detections) of up to 575âkm and over 100âdays at sea were described for all 25 populations. Post-smolts from different rivers, as well as individuals from the same river, used different pathways in coastal waters. Although difficult to generalize to all rivers, at least during the year of this study, no tagged post-smolts from rivers draining into the Irish Sea were detected entering the areas of sea between the Hebrides and mainland Scotland, which is associated with a high density of finfish aquaculture. An important outcome of this study is that a high proportion of post-smolts crossed through multiple legislative jurisdictions and boundaries during their migration. This study provides the basis for spatially explicit assessment of the impact risk of coastal pressures on salmon during their first migration to sea
Continuum Reverberation Mapping of the Accretion Disks in Two Seyfert 1 Galaxies
K.H.acknowledges support from STFC grant ST/M001296/1.We present optical continuum lags for two Seyfert 1 galaxies, MCG+08-11-011 and NGC 2617, using monitoring data from a reverberation mapping campaign carried out in 2014. Our light curves span the ugriz filters over four months, with median cadences of 1.0 and 0.6 days for MCG+08-11-011 and NGC 2617, respectively, combined with roughly daily X-ray and near-UV data from Swift for NGC 2617. We find lags consistent with geometrically thin accretion-disk models that predict a lag-wavelength relation of Ï â λ 4/3. However, the observed lags are larger than predictions based on standard thin-disk theory by factors of 3.3 for MCG+08-11-011 and 2.3 for NGC 2617. These differences can be explained if the mass accretion rates are larger than inferred from the optical luminosity by a factor of 4.3 in MCG+08-11-011 and a factor of 1.3 in NGC 2617, although uncertainty in the SMBH masses determines the significance of this result. While the X-ray variability in NGC 2617 precedes the UV/optical variability, the long (2.6 day) lag is problematic for coronal reprocessing models.Publisher PDFPeer reviewe