Even More Spectra: Tensor Triangular Comparison Maps via Graded Commutative 2-rings

We initiate the theory of graded commutative 2-rings, a categorification of graded commutative rings. The goal is to provide a systematic generalization of Paul Balmer’s comparison maps between the spectrum of tensor-triangulated categories and the Zariski spectra of their central rings. By applying our constructions, we compute the spectrum of the derived category of perfect complexes over any graded commutative ring, and we associate to every scheme with an ample family of line bundles an embedding into the spectrum of an associated graded commutative 2-ring.     

Quantum computation with Turaev-Viro codes

For a 3-manifold with triangulated boundary, the Turaev-Viro topological invariant can be interpreted as a quantum error-correcting code. The code has local stabilizers, identified by Levin and Wen, on a qudit lattice. Kitaev’s toric code arises as a special case. The toric code corresponds to an abelian anyon model, and therefore requires out-of-code operations to obtain universal quantum computation. In contrast, for many categories, such as the Fibonacci category, the Turaev-Viro code realizes a non-abelian anyon model. A universal set of fault-tolerant operations can be implemented by deforming the code with local gates, in order to implement anyon braiding. We identify the anyons in the code space, and present schemes for initialization, computation and measurement. This provides a family of constructions for fault-tolerant quantum computation that are closely related to topological quantum computation, but for which the fault tolerance is implemented in software rather than coming from a physical medium.     

First dark matter search results from the PandaX-I experiment

We report on the first dark-matter (DM) search results from PandaX-I, a low threshold dual-phase xenon experiment operating at the China JinPing Underground Laboratory. In the 37-kg liquid xenon target with 17.4 live-days of exposure, no DM particle candidate event was found. This result sets a stringent limit for low-mass DM particles and disfavors the interpretation of previously-reported positive experimental results. The minimum upper limit, 3.7 × 10^?44 cm², for the spin-independent isoscalar DM-particle-nucleon scattering cross section is obtained at a DM-particle mass of 49GeV/c² at 90% confidence level.     

Rotational frequency shifts for electromagnetic fields of arbitrary states of coherence and polarization

The rotational frequency shift is studied for fields of arbitrary states of coherence and polarization. It is shown that the power spectrum of the field in the rotating frame is influenced both by the degree of polarization and the degree of coherence. Examples for some model field classes are given.     

Electrophoretic collision of a DNA molecule with an insulating post

We study the dynamics of single DNA molecules driven by an electric field into a stationary obstacle. These collisions are broadly classified as "hook" and "roll-off" events. We show that obstacle-induced electric field gradients stretch impacting DNA and thus greatly influence the hooking probability. Consequently, in addition to collision geometry, determination of the hooking probability depends on the Deborah number (De) for 0.5相似文献   

The acoustic and visual factors influencing the construction of tranquil space in urban and rural environments tranquil spaces-quiet places?

Prior to this work no structured mechanism existed in the UK to evaluate the tranquillity of open spaces with respect to the characteristics of both acoustic and visual stimuli. This is largely due to the fact that within the context of "tranquil" environments, little is known about the interaction of the audio-visual modalities and how they combine to lead to the perception of tranquillity. This paper presents the findings of a study in which visual and acoustic data, captured from 11 English rural and urban landscapes, were used by 44 volunteers to make subjective assessments of both their perceived tranquillity of a location, and the loudness of five generic soundscape components. The results were then analyzed alongside objective measurements taken in the laboratory. It was found that the maximum sound pressure level (L(Amax)) and the percentage of natural features present at a location were the key factors influencing tranquillity. Engineering formulas for the tranquillity as a function of the noise level and proportion of the natural features are proposed.     

Measurement of airborne sound insulation of timber noise barriers: Comparison of in situ method CEN/TS 1793-5 with laboratory method EN 1793-2

Recent progress in the development of European standards has allowed the in situ testing of roadside noise barriers. CEN/TS 1793-5 describes a test method using maximum length sequences (MLS) for the characterisation of airborne sound insulation. However, many barriers are tested according to a laboratory standard, EN 1793-2, based on measurements carried out in reverberant chambers and in the case of timber barriers with a relatively low airborne sound insulation it is not clear to what extent the results of the two tests compare. The paper describes the results of tests carried out using both methods. Six samples of timber barrier were compared including single-leaf and double-leaf constructions and single-leaf constructions with an absorptive core. Very good agreement was found especially when account was taken of the valid frequency range in each test method. The results open up the possibility of routinely evaluating the performance of timber barriers at the roadside where build quality can be variable and there are concerns that the acoustic performance may not match that obtained under laboratory test conditions where typically the barrier is more carefully constructed.     

Phase and coherence singularities generated by the interference of partially coherent fields

A condition for the complete destructive interference of partially coherent fields emerging from pinholes in an opaque screen is derived, with the assumption of symmetry in both their geometric positions and coherence properties. We use this condition to theoretically investigate the simultaneous production of phase singularities of the optical field and of the spectral degree of coherence. We find that in cases where the number of point sources is even, a new type of mixed field/correlation singularity is observed.