Abstract
We present a model of an externally driven acoustic metamaterial constituted of a nonlinear parallel array of coupled acoustic waveguides that supports logical phi-bits, classical analogues ...of quantum bits (qubit). Descriptions of correlated multiple phi-bit systems emphasize the importance of representations of phi-bit and multiple phi-bit vector states within the context of their corresponding Hilbert space. Experimental data are used to demonstrate the realization of the single phi-bit Hadamard gate and the phase shift gate. A three phi-bit system is also used to illustrate the development of multiple phi-bit gates as well as a simple quantum-like algorithm. These demonstrations set the stage for the implementation of a digital quantum analogue computing platform based on acoustic metamaterial that can implement quantum-like gates and may offer promise as an efficient platform for the simulation of materials.
Abstract
We show how spectra of Type Ia supernovae (SNe Ia) at maximum light can be used to improve cosmological distance estimates. In a companion article, we used manifold learning to build a ...three-dimensional parameterization of the intrinsic diversity of SNe Ia at maximum light that we call the “Twins Embedding.” In this article, we discuss how the Twins Embedding can be used to improve the standardization of SNe Ia. With a single spectrophotometrically calibrated spectrum near maximum light, we can standardize our sample of SNe Ia with an rms of 0.101 ± 0.007 mag, which corresponds to 0.084 ± 0.009 mag if peculiar velocity contributions are removed and to 0.073 ± 0.008 mag if a larger reference sample were obtained. Our techniques can standardize the full range of SNe Ia, including those typically labeled as peculiar and often rejected from other analyses. We find that traditional light-curve width + color standardization such as SALT2 is not sufficient. The Twins Embedding identifies a subset of SNe Ia, including, but not limited to, 91T-like SNe Ia whose SALT2 distance estimates are biased by 0.229 ± 0.045 mag. Standardization using the Twins Embedding also significantly decreases host-galaxy correlations. We recover a host mass step of 0.040 ± 0.020 mag compared to 0.092 ± 0.026 mag for SALT2 standardization on the same sample of SNe Ia. These biases in traditional standardization methods could significantly impact future cosmology analyses if not properly taken into account.
We present a sample of normal Type Ia supernovae (SNe Ia) from the Nearby Supernova Factory data set with spectrophotometry at sufficiently late phases to estimate the ejected mass using the ...bolometric light curve. We measure 56Ni masses from the peak bolometric luminosity, then compare the luminosity in the 56Co-decay tail to the expected rate of radioactive energy release from ejecta of a given mass. We infer the ejected mass in a Bayesian context using a semi-analytic model of the ejecta, incorporating constraints from contemporary numerical models as priors on the density structure and distribution of 56Ni throughout the ejecta. We find a strong correlation between ejected mass and light-curve decline rate, and consequently 56Ni mass, with ejected masses in our data ranging from 0.9 to 1.4 M. Most fast-declining (salt2
x
1 < −1) normal SNe Ia have significantly sub-Chandrasekhar ejected masses in our fiducial analysis.
The analogy between acoustic modes in nonlinear metamaterials and quantum computing platforms constituted of correlated two-level systems opens new frontiers in information science. We use an ...inductive procedure to demonstrate scalable initialization of and scalable unitary transformations on superpositions of states of multiple correlated logical phi-bits, classical nonlinear acoustic analog of qubits. A multiple phi-bit state representation as a complex vector in a high-dimensional, exponentially scaling Hilbert space is shown to correspond with the state of logical phi-bits represented in a low-dimensional linearly scaling physical space of an externally driven acoustic metamaterial. Manipulation of the phi-bits in the physical space enables the implementation of a non-trivial multiple phi-bit unitary transformation that scales exponentially. This scalable transformation operates in parallel on the components of the multiple phi-bit complex state vector, requiring only a single physical action on the metamaterial. This work demonstrates that acoustic metamaterials offer a viable path toward achieving massively parallel information processing capabilities that can challenge current quantum computing paradigms.
•Frother type and concentration adjust gangue particle motion relative to water.•Frother effect on ENT is a result of water motion at the pulp/froth interface.•Frother affects water velocity and thus ...the drag at interface in determining ENT.•The classification of entrained particles mainly occurs at the pulp/froth interface.
The effect of frothers on the degree of entrainment is important for selective flotation, but the mechanism underpinning the effect is still poorly understood. In this study, gangue only batch flotation tests were performed using fully liberated quartz in a 3.5L conventional Agitair flotation cell, and the degree of entrainment was assessed at different frother concentrations using Dowfroth 250 and MIBC. Results show that the effect of frothers on the degree of entrainment was the consequence of changes in the upward liquid motion across the pulp/froth interface. The frothers changed the bubble size, resulting in a change in liquid content and liquid velocity at the interface. The change in interface liquid velocity then changed the drag force which determined the motion of a particle against the downward gravitational force on the particle due to its weight, resulting in a change in the amount of hydrophilic solid particles following the water phase and being recovered in the water phase, and hence the degree of entrainment. The results also suggest that the classification of hydrophilic solid particles occurred at the interface region.
We demonstrate theoretically, using multiple-time-scale perturbation theory, the existence of nonseparable superpositions of elastic waves in an externally driven elastic system composed of three ...one-dimensional elastic wave guides coupled via nonlinear forces. The nonseparable states span a Hilbert space with exponential complexity. The amplitudes appearing in the nonseparable superposition of elastic states are complex quantities dependent on the frequency of the external driver. By tuning these complex amplitudes, we can navigate the state’s Hilbert space. This nonlinear elastic system is analogous to a two-partite two-level quantum system.
A planar array of three one-dimensional elastic waveguides mutually coupled periodically along their length and driven externally is shown theoretically and numerically to support nonseparable ...superpositions of states. These states are the product of Bloch waves describing the elastic displacement along the waveguides and spatial modes representing the displacement across the array of waveguides. For a system composed of finite length waveguides, the frequency, relative amplitude, and phase of the external drivers can be employed to selectively excite specific groups of discrete product modes. The periodicity of the coupling is used to fold bands enabling superpositions of states that span the complete Hilbert space of product states. We show that we can realize a transformation from one type of nonseparable superposition to another one that is analogous to a nontrivial quantum gate. This transformation is also interpreted as the complex conjugation operator in the space of the complex amplitudes of individual waveguides.
Abstract
We study the spectral diversity of Type Ia supernovae (SNe Ia) at maximum light using high signal-to-noise spectrophotometry of 173 SNe Ia from the Nearby Supernova Factory. We decompose the ...diversity of these spectra into different extrinsic and intrinsic components, and we construct a nonlinear parameterization of the intrinsic diversity of SNe Ia that preserves pairings of “twin” SNe Ia. We call this parameterization the “Twins Embedding.” Our methodology naturally handles highly nonlinear variability in spectra, such as changes in the photosphere expansion velocity, and uses the full spectrum rather than being limited to specific spectral line strengths, ratios, or velocities. We find that the time evolution of SNe Ia near maximum light is remarkably similar, with 84.6% of the variance in common to all SNe Ia. After correcting for brightness and color, the intrinsic variability of SNe Ia is mostly restricted to specific spectral lines, and we find intrinsic dispersions as low as ∼0.02 mag between 6600 and 7200 Å. With a nonlinear three-dimensional model plus one dimension for color, we can explain 89.2% of the intrinsic diversity in our sample of SNe Ia, which includes several different kinds of “peculiar” SNe Ia. A linear model requires seven dimensions to explain a comparable fraction of the intrinsic diversity. We show how a wide range of previously established indicators of diversity in SNe Ia can be recovered from the Twins Embedding. In a companion article, we discuss how these results can be applied to the standardization of SNe Ia for cosmology.
Introduction
The development of the 11th edition of the International Classification of Diseases has rekindled the research interest surrounding diagnostic classification systems (DCSs). According to ...expert consensus, the main purpose of DCSs is to provide guidance in clinical practice. There are no reviews in the international literature, however, assessing what mental health practitioners believe is the main purpose of DCSs.
Objectives
The aims of this systematic review were to assess what mental health professionals think is the single most important purpose of DCSs and how they rate DCSs’ utility for various purposes. All DCSs were considered.
Methods
Two separate searches were conducted in Medline Via Ovid and PsycInfo: one for articles assessing the main purpose of DCSs according to mental health professionals and one for studies on how practitioners rate the utility of DCSs for various purposes. The first search revealed eight articles on the main purpose of DCSs and the second three articles on how practitioners rate their utility for various purposes. The total number of participants from all included studies for the first search was 9,276 and for the second 2,363. The studies included clinicians from a wide range of world regions, languages, and income-level countries.
Results
The results of the meta-analyses for the first search showed that 44% (95%CI=38-49%) of the responders believe that the main purpose of the DCSs is facilitating inter-clinician communication, 20% (4-35%) to inform treatment decisions, 14% (11-16%) to aid the communication between clinicians and patients, 11% (4-18%) to reflect on aetiology/pathogenesis, 9% (2-16%) to facilitate research, 4% (2-7%) to provide a national statistical base and 1% (0.1-2%) to indicate prognosis. Regarding how responders rate the utility of DCSs for various purposes, the highest ratings were given for meeting administrative requirements and inter-clinician communication in the two of the three included studies, and clinical diagnosis and training in the third.
Conclusions
“Inter-clinician communication” was the most voted purpose of DCSs and was rated relatively high in the tier of DCSs’ clinical utility. In contrast, “inform management decisions”, even though it was voted as the second most popular purpose of DCSs, was placed on the bottom of the rating tier of DCSs’ clinical utility. Interestingly, none of the included studies asked the responders whether “making a diagnosis” is the main purpose of DCSs. Further research is needed to assess what mental health professionals expect from DCSs, so as to improve their clinical utility in the future.
Disclosure of Interest
None Declared
We herein investigate the scattering of orthogonal counterpropagating waves and one-way propagating bulk waves in discrete acoustic superlattices subjected to a scattering potential applied to one of ...the superlattice unit cells. We demonstrate theoretically that the orthogonality of counterpropagating modes does not provide robust protection against backscattering. By contrast, the one-way propagating modes do satisfy a no-reflection condition, i.e., they exhibit immunity to backscattering, for a wide range of applied scattering potentials, which represent defects and disorder.
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