Read by QxMD icon Read

String theory

Piotr Tourkine, Pierre Vanhove
The monodromy relations in string theory provide a powerful and elegant formalism to understand some of the deepest properties of tree-level field theory amplitudes, like the color-kinematics duality. This duality has been instrumental in tremendous progress on the computations of loop amplitudes in quantum field theory, but a higher-loop generalization of the monodromy construction was lacking. In this Letter, we extend the monodromy relations to higher loops in open string theory. Our construction, based on a contour deformation argument of the open string diagram integrands, leads to new identities that relate planar and nonplanar topologies in string theory...
November 18, 2016: Physical Review Letters
Antoine Chaigne
A method is presented for reconstructing piano hammer forces through appropriate filtering of the measured string velocity. The filter design is based on the analysis of the pulses generated by the hammer blow and propagating along the string. In the five lowest octaves, the hammer force is reconstructed by considering two waves only: the incoming wave from the hammer and its first reflection at the front end. For the higher notes, four- or eight-wave schemes must be considered. The theory is validated on simulated string velocities by comparing imposed and reconstructed forces...
November 2016: Journal of the Acoustical Society of America
Tongjie Sun, Ping Tang, Feng Qiu, An-Chang Shi
Applying the string method to the self-consistent field theory (SCFT) of ABC linear triblock copolymers, we developed a new strategy to design kinetic pathways for the formation of stable or metastable network mesophases in order-order transition (OOT) processes. The design principle regarding the kinetic pathways between distinct mesophases is based on the matching relationships of both domain spacing and dominant Fourier components of the density distributions. The results suggest that complex ordered network mesophases, such as alternating diamond (D(A)) and alternating plumber's nightmare (P(A)) could be obtained in kinetic pathways between simple phases covering lamellae, cylinders and spheres...
November 29, 2016: Soft Matter
Yuho Sakatani, Shozo Uehara
We propose a novel approach to the brane worldvolume theory based on the geometry of extended field theories: double field theory and exceptional field theory. We demonstrate the effectiveness of this approach by showing that one can reproduce the conventional bosonic string and membrane actions, and the M5-brane action in the weak-field approximation. At a glance, the proposed 5-brane action without approximation looks different from the known M5-brane actions, but it is consistent with the known nonlinear self-duality relation, and it may provide a new formulation of a single M5-brane action...
November 4, 2016: Physical Review Letters
Bobby S Acharya, Sebastian A R Ellis, Gordon L Kane, Brent D Nelson, Malcolm J Perry
We argue, based on typical properties of known solutions of string or M theory, that the lightest supersymmetric particle of the visible sector is likely to be unstable. In other words, dark matter is probably not a particle with standard model quantum numbers, such as a weakly interacting massive particle. The argument is simple and based on the typical occurrence of (a) hidden sectors, (b) interactions between the standard model (visible) sector and these hidden sectors, and (c) the lack of an argument against massive neutral hidden sector particles being lighter than the lightest visible supersymmetric particle...
October 28, 2016: Physical Review Letters
Karin Jarnkvist, Lotta Brännström
The objective of this article is to analyze how women who have been victims of intimate partner violence (IPV) position themselves in relation to the image of the "ideal victim" and how gender is constructed in that positioning. There is a need for a gender analysis framework to understand how various forms of femininity are constructed and how narratives linked to this can either maintain a woman in an abusive relationship or encourage her to leave. Christie's theory of the "ideal victim" and Connell's gender theory are applied in this study, in which the narratives of 14 female IPV victims in Sweden are analyzed using a narrative method...
November 8, 2016: Journal of Interpersonal Violence
David Garfinkle
Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black holes and in big bang cosmology...
November 7, 2016: Reports on Progress in Physics
Pavel Janoš, Tomáš Trnka, Stanislav Kozmon, Igor Tvaroska, Jaroslav Koča
Hybrid QM/MM computational studies can provide invaluable insight into the mechanisms of enzymatic reactions that can be exploited for rational drug design. Various approaches are available for such studies. However, their strengths and weaknesses may not be immediately apparent. Using the retaining glycosyltransferase ppGalNAcT2 as a case study, we compare different methodologies used to obtain reaction paths and transition state information. Ab Initio MD using CPMD coupled with String Method is used to derive the minimum free energy reaction path...
October 27, 2016: Journal of Chemical Theory and Computation
Athanasios Ch Mitropoulos, Evangelos P Favvas, Konstantinos L Stefanopoulos, Etienne F Vansant
Everett's theorem-6 of the domain theory was examined by conducting adsorption in situ with small angle x-ray scattering (SAXS) supplemented by the contrast matching technique. The study focuses on the spectrum differences of a point to which the system arrives from different scanning paths. It is noted that according to this theorem at a common point the system has similar macroscopic properties. Furthermore it was examined the memory string of the system. We concluded that opposite to theorem-6: a) at a common point the system can reach in a finite (not an infinite) number of ways, b) a correction for the thickness of the adsorbed film prior to capillary condensation is necessary, and c) the scattering curves although at high-Q values coincide, at low-Q values are different indicating different microscopic states...
2016: PloS One
Carleigh B Krubiner, Maria W Merritt
Conditional cash transfers (CCTs) present a promising approach to simultaneously tackle chronic poverty and poor health. While these programmes clearly embody beneficent aims, questions remain regarding the ethical design of CCTs. Limited guidance exists for the ethical evaluation of the defining feature of these programmes: the conditionalities. Drawing upon prominent public health ethics frameworks and social justice theories, this paper outlines five categories of morally relevant considerations that CCT programme designers should consider when assessing which behaviours or outcomes they select as conditionalities for payment: (1) likelihood of yielding desired health outcomes, (2) risks and burdens, (3) receptivity, (4) attainability and (5) indirect impacts and externalities...
October 5, 2016: Journal of Medical Ethics
Ravini Jayawardena, Heather Winskel
The current study aimed to test the applicability of the modified receptive field (MRF) theory (Tydgat & Grainger, 2009) with English native speakers (Experiment 1) and Sinhalese native speakers (Experiment 2), who were skilled readers of both Sinhala and Roman scripts. A two-alternative forced choice (2AFC) procedure to measure identification accuracy for all positions in a string of five characters, which consisted of Roman script letters, Sinhala letters or symbols was conducted. For Roman script, the English and Sinhalese speakers displayed analogous results as in previous studies for Roman letters and symbols (i...
September 23, 2016: Acta Psychologica
Robert J Robbins, Leonard Krishtalka, John C Wooley
BACKGROUND: Efforts to harmonize genomic data standards used by the biodiversity and metagenomic research communities have shown that prokaryotic data cannot be understood or represented in a traditional, classical biological context for conceptual reasons, not technical ones. RESULTS: Biology, like physics, has a fundamental duality-the classical macroscale eukaryotic realm vs. the quantum microscale microbial realm-with the two realms differing profoundly, and counter-intuitively, from one another...
2016: Standards in Genomic Sciences
Wei Song, Qiang Wen, Jianfei Xu
For spacetimes that are not asymptotic to anti-de Sitter (non AAdS) space, we adapt the Lewkowycz-Maldacena procedure to find the holographic entanglement entropy. The key observation, which to our knowledge is not very well appreciated, is that asymptotic boundary conditions play an essential role on extending the replica trick to the bulk. For non AAdS, we expect the following three main modifications: (1) the expansion near the special surface has to be compatible with the asymptotic expansion; (2) periodic conditions are imposed to coordinates on the phase space with diagonalized symplectic structure, not to all fields appearing in the action; (3) evaluating the entanglement functional using the boundary term method amounts to evaluating the presymplectic structure at the special surface, where some additional exact form may contribute...
July 1, 2016: Physical Review Letters
Jun Li, Fu-Kuo Chiang, Zhen Chen, Chao Ma, Ming-Wen Chu, Cheng-Hsuan Chen, Huanfang Tian, Huaixin Yang, Jianqi Li
Essential structural properties of the non-trivial "string-wall-bounded" topological defects in hexagonal manganites are studied through homotopy group theory and spherical aberration-corrected scanning transmission electron microscopy. The appearance of a "string-wall-bounded" configuration in RMnO3 is shown to be strongly linked with the transformation of the degeneracy space. The defect core regions (~50 Å) mainly adopt the continuous U(1) symmetry of the high-temperature phase, which is essential for the formation and proliferation of vortices...
2016: Scientific Reports
Bagavathy Shanmugam Karthikeyan, Mohammad Abdulkader Akbarsha, Subbiah Parthasarathy
Cytochrome P450 (CYP) enzymes that degrade xenobiotics play a critical role in the metabolism and biotransformation of drugs and xenobiotics in humans as well as experimental animal models such as mouse and rat. These proteins function as a network collectively as well as independently. Though there are several reports on the organization, regulation and functionality of various CYP enzymes at the molecular level, the understanding of organization and functionality of these proteins at the holistic level remain unclear...
June 21, 2016: Molecular BioSystems
Fabian Maucher, Paul Sutcliffe
We introduce and illustrate a new approach to the unknotting problem via the dynamics of vortex strings in a nonlinear partial differential equation of reaction-diffusion type. To untangle a given knot, a Biot-Savart construction is used to initialize the knot as a vortex string in the FitzHugh-Nagumo equation. Remarkably, we find that the subsequent evolution preserves the topology of the knot and can untangle an unknot into a circle. Illustrative test case examples are presented, including the untangling of a hard unknot known as the culprit...
April 29, 2016: Physical Review Letters
Qing Wang, Changhou Lu, Ran Huang, Wei Pan, Xueyong Li
Yarn tension is an important parameter for assuring textile quality. In this paper, an optical method to measure microtension of moving yarn automatically in the winding system is proposed. The proposed method can measure microtension of the moving yarn by analyzing the captured images. With a line laser illuminating the moving yarn, a linear array CCD camera is used to capture the images. Design principles of yarn microtension measuring equipment based on computer vision are presented. A local border difference algorithm is used to search the upper border of the moving yarn as the characteristic line, and Fourier descriptors are used to filter the high-frequency noises caused by unevenness of the yarn diameter...
March 20, 2016: Applied Optics
Amit Samanta, Miguel A Morales, Eric Schwegler
Efficient exploration of configuration space and identification of metastable structures in condensed phase systems are challenging from both computational and algorithmic perspectives. In this regard, schemes that utilize a set of pre-defined order parameters to sample the relevant parts of the configuration space [L. Maragliano and E. Vanden-Eijnden, Chem. Phys. Lett. 426, 168 (2006); J. B. Abrams and M. E. Tuckerman, J. Phys. Chem. B 112, 15742 (2008)] have proved useful. Here, we demonstrate how these order-parameter aided temperature accelerated sampling schemes can be used within the Born-Oppenheimer and the Car-Parrinello frameworks of ab initio molecular dynamics to efficiently and systematically explore free energy surfaces, and search for metastable states and reaction pathways...
April 28, 2016: Journal of Chemical Physics
Hitoshi Koyano, Morihiro Hayashida, Tatsuya Akutsu
Numbers and numerical vectors account for a large portion of data. However, recently, the amount of string data generated has increased dramatically. Consequently, classifying string data is a common problem in many fields. The most widely used approach to this problem is to convert strings into numerical vectors using string kernels and subsequently apply a support vector machine that works in a numerical vector space. However, this non-one-to-one conversion involves a loss of information and makes it impossible to evaluate, using probability theory, the generalization error of a learning machine, considering that the given data to train and test the machine are strings generated according to probability laws...
March 2016: Proceedings. Mathematical, Physical, and Engineering Sciences
Iosif Bena, Mariana Graña, Stanislav Kuperstein, Praxitelis Ntokos, Michela Petrini
A common way to obtain standard-model-like Lagrangians in string theory is to place D3-branes inside flux compactifications. The bosonic and fermionic masses and couplings of the resulting gauge theory are determined by the ten-dimensional metric and the fluxes, respectively, and the breaking of supersymmetry is soft. However, not any soft-supersymmetry-breaking Lagrangian can be obtained this way since the string theory equations of motion impose certain relations between the soft couplings. We show that for D3-branes in background fluxes, these relations imply that the sums of the squares of the boson and of the fermion masses are equal and that, furthermore, one- and two-loop quantum corrections do not spoil this equality...
April 8, 2016: Physical Review Letters
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"