Angle Theta Research Articles

Supersymmetric gauge theory with space-time-dependent couplings

We study deformations of ${\cal N}=4$ supersymmetric Yang-Mills theory with couplings and masses depending on space-time. The conditions to preserve part of the supersymmetry are derived and a lot of solutions of these conditions are found. The main example is the case with $ISO(1,1)\times SO(3)\times SO(3)$ symmetry, in which couplings, as well as masses and the theta parameter, can depend on two spatial coordinates. In the case $ISO(1,1)$ is enhanced to $ISO(1,2)$, it reproduces the supersymmetric Janus configuration found by Gaiotto and Witten. When $SO(3)\times SO(3)$ is enhanced to $SO(6)$, it agrees with the world-volume theory of D3-branes embedded in F-theory (a background with 7-branes in type IIB string theory). We also find the general solution of the supersymmetry conditions for the cases with $ISO(1,1)\times SO(2)\times SO(4)$ symmetry. The cases with time dependent couplings and/or masses are also considered.

Preservation of Quantum Fisher Information and Geometric Phase of a Single Qubit System in a Dissipative Reservoir Through the Addition of Qubits

In this paper, we have investigated the preservation of quantum Fisher information of a single-qubit system coupled to a common zero temperature reservoir through the addition of noninteracting qubits. The results show that, the QFI is completely protected in both Markovian and non-Markovian regimes by increasing the number of additional qubits. Besides, the phenomena of QFI display monotonic decay or non-monotonic with revival oscillations depending on the number of additional qubits in a common dissipative reservoir. Moreover, we extend this model to investigate the effect of additional qubits N-1 and the initial conditions of the system on the geometric phase. It is found that, the robustness of GP against the dissipative reservoir has been demonstrated by increasing gradually the number of additional qubits. Besides, the GP is sensitive to the initial parameter theta, and possesses symmetric in a range regime 0,2 pi.

Spontaneous CP breaking in QCD and the axion potential: an effective Lagrangian approach

Using the well-known low-energy effective Lagrangian of QCD — valid for small (non-vanishing) quark masses and a large number of colors — we study in detail the regions of parameter space where CP is spontaneously broken/unbroken for a vacuum angle θ = π. In the CP broken region there are first order phase transitions as one crosses θ = π, while on the (hyper)surface separating the two regions, there are second order phase transitions signalled by the vanishing of the mass of a pseudo Nambu-Goldstone boson and by a divergent QCD topological susceptibility. The second order point sits at the end of a first order line associated with the CP spontaneous breaking, in the appropriate complex parameter plane. When the effective Lagrangian is extended by the inclusion of an axion these features of QCD imply that standard calculations of the axion potential have to be revised if the QCD parameters fall in the above mentioned CP broken region, in spite of the fact that the axion solves the strong-CP problem. These last results could be of interest for axionic dark matter calculations if the topological susceptibility of pure Yang-Mills theory falls off sufficiently fast when temperature is increased towards the QCD deconfining transition.

Parameter estimation for nonergodic Ornstein-Uhlenbeck process driven by the weighted fractional Brownian motion

In this paper, we consider the nonergodic Ornstein-Uhlenbeck process X0=0,dXt=θXtdt+dBta,b,t≥0,\\documentclass[12pt]{minimal}\t\t\t\t\\usepackage{amsmath}\t\t\t\t\\usepackage{wasysym}\t\t\t\t\\usepackage{amsfonts}\t\t\t\t\\usepackage{amssymb}\t\t\t\t\\usepackage{amsbsy}\t\t\t\t\\usepackage{mathrsfs}\t\t\t\t\\usepackage{upgreek}\t\t\t\t\\setlength{\\oddsidemargin}{-69pt}\t\t\t\t\\begin{document}$$ X_{0}=0, \\quad\\quad dX_{t}=\\theta X_{t} \\,dt+dB_{t}^{a,b},\\quad t\\geq0, $$\\end{document} driven by the weighted fractional Brownian motion B_{t}^{a,b} with parameter a and b. Our goal is to estimate the unknown parameter theta>0 based on the discrete observations of the process. We construct two estimators hat{theta}_{n} and check{theta}_{n} of θ and show their strong consistency and the rate consistency.

Oxygen partial pressure effects on the RF sputtered p-type NiO hydrogen gas sensors

NiO thin films were grown by Radio Frequency (RF) Magnetron Sputtering method under different oxygen partial pressures, which are 0.6 mTorr, 1.3 mTorr and 2.0 mTorr. The effects of oxygen partial pressures on the thin films were analyzed through Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Hall measurements. The change in the surface morphology of the thin films has been observed with the SEM and AFM measurements. While nano-pyramids have been obtained on the thin film grown at the lowest oxygen partial pressure, the spherical granules lower than 60 nm in size has been observed for the samples grown at higher oxygen partial pressures. The shift in the dominant XRD peak is realized to the lower two theta angle with increasing the oxygen partial pressures. XPS measurements showed that the Ni2p peak involves satellite peaks and two oxidation states of Ni, Ni2+ and Ni3+, have been existed together with the corresponding splitting in O1s spectrum. P-type conductivity of the grown NiO thin films are confirmed by the Hall measurements with concentrations on the order of 1013 holes/cm−3. Gas sensor measurements revealed minimum of 10% response to the 10 ppm H2 level. Enhanced responsivity of the gas sensor devices of NiO thin films is shown as the oxygen partial pressure increases.

Discrete theta angle from an O5-plane

We consider 5d mathcal{N} = 1 Sp(1) gauge theory based on a brane configuration with an O5-plane. At the UV fixed point, the theory with no matter enjoys enhanced global symmetry SU(2) or U(1) depending on the discrete theta angle θ = 0, π (mod 2π). A naive brane configuration with an O5-plane, however, does not distinguish two different theories, as it describes the weak coupling region. We devise a technique for computing 5d Seiberg-Witten curve of the two theories from the brane web with an O5-plane. Their Seiberg-Witten curves show that their M5 configurations under the presence of OM5-planes are different. The decompactification limit of each Seiberg-Witten curve also shows distinct phase structures in their Coulomb branch leading to significantly different (p, q) 5-brane configurations with an O5-plane in the strong coupling region.

Instantons and entanglement entropy

We would like to put the area law — believed to be obeyed by entanglement entropies in the ground state of a local field theory — to scrutiny in the presence of nonperturbative effects. We study instanton corrections to entanglement entropy in various models whose instanton contributions are well understood, including U(1) gauge theory in 2+1 dimensions and false vacuum decay in ϕ4 theory, and we demonstrate that the area law is indeed obeyed in these models. We also perform numerical computations for toy wavefunctions mimicking the theta vacuum of the (1+1)-dimensional Schwinger model. Our results indicate that such superpositions exhibit no more violation of the area law than the logarithmic behavior of a single Fermi surface.

The minimal flavour violating axion

The solution to the Strong CP problem is analysed within the Minimal Flavour Violation (MFV) context. An Abelian factor of the complete flavour symmetry of the fermionic kinetic terms may play the role of the Peccei-Quinn symmetry in traditional axion models. Its spontaneous breaking, due to the addition of a complex scalar field to the Standard Model scalar spectrum, generates the MFV axion, which may redefine away the QCD theta parameter. It differs from the traditional QCD axion for its couplings that are governed by the fermion charges under the axial Abelian symmetry. It is also distinct from the so-called Axiflavon, as the MFV axion does not describe flavour violation, while it does induce flavour non-universality effects. The MFV axion phenomenology is discussed considering astrophysical, collider and flavour data.

Vagus nerve stimulation produces a hippocampal formation theta rhythm in anesthetized rats

Vagus nerve stimulation (VNS) has been used for years to treat patients with drug-resistant epilepsy. In the present study, the effect of different stimulation protocols of VNS on the hippocampal formation (HPC) type II theta field potentials were evaluated in anesthetized rats. The following theta parameters were analysed: power, frequency and duration of theta epochs. We documented for the first time the presence of HPC type II theta in response to the application of VNS. A VNS-induced theta rhythm appeared in different experimental protocols and, depending on the current intensity, could occur directly during VNS (brief effect) or after vagal stimulation (delayed effect), using lower intensity stimuli.

An Accurate Method for Determining Pattern Collapse Occurrence for Nano-Structures

Introduction In order to prevent pattern collapse, various drying technologies have been developed, such as isopropyl alcohol(IPA) dry, sublimation dry, supercritical dry, and surface modification agent treatment dry. It is important to fully understand the pattern collapse prevention performance of each drying technology in order to promptly determine a sustainable solution. In general, space aspect ratio (space AR), which consists of two parameters, pattern height and space, is often used as the indicator for determining the likelihood of pattern collapse occurrence, because high aspect ratio structures tend to collapse more easily. However, pattern collapse is also influenced by flexural rigidity of the structures, pattern thickness, material, and shape. Therefore, space AR lacks versatility in comparing different structures. We propose “GammaPC ” as the new parameter for pattern collapse occurrence. In this paper, we indicate with experimental data that GammaPC can be used to accurately assess the pattern collapse prevention performance of drying technologies. Theory Two structure models, line and pillar, with rinse liquid present in one of the grooves are considered (Figure1). The patterns are subjected to the uniformly distributed load P caused by Laplace Pressure over the span L. The deflection delta of patterns is given as Equation1 where E is Young modulus, I is moment of inertia of area, t is thickness and W is width. The distributed load P is given as Equation2 where S is space, gamma is surface tension of rinse liquid, theta is contact angle(theta is set to 0 in this paper). Equation1 is rearranged about gamma with Equation2 and delta=S/2. As a result, Equation3 is obtained and we define the surface tension on this condition as GammaPC (Gamma Pattern Contact)When the deflection delta is equal to half of space (S/2), the walls of the groove collapse in and make contact. Therefore, GammaPC means the threshold of pattern collapse occurrence. Structures with small GammaPC collapse easily with minimal force. Structures with large GammaPC are less likely to collapse. GammaPC gives us approximate information about the mechanical strength of structures. Results and Discussion We prepared four 90nm pitch pillar patterned samples of silicon (E=130GPa) with heights ranging from 380nm to 455nm, and four 40nm pitch line patterned samples of silicon oxide (E=75GPa) with heights ranging from 250nm to 330nm. At first, the height and width of the pattern were measured by scatterometory, and space AR and GammaPC were calculated. Next, we tested three drying methods: IPA spin dry; IPA scan dry; and Surface Modification Dry (SMD). Figure 2 shows scatter diagrams of the pattern collapse ratio of space AR and GammaPC . With space AR, the plots are scattered widely, and are divided into two groups by structure pattern. On the other hand, the pattern collapse ratio of GammaPC begins to increase at a certain value of GammaPC with each drying technology. The value of GammaPC indicates the pattern collapse prevention performance. So the structures with a GammaPC value of less than about 4-5 need a dry technology with a higher performance than SMD. Notably, the tendency is almost the same even with different structures. GammaPC can indicate the dry technology performance for pattern collapse occurrence more precisely and quantitatively than space AR. Conclusion We propose GammaPC as the new parameter of pattern collapse occurrence. Unlike space AR, GammaPC is calculated with not only pattern height and space, but also thickness, material, and shape. Therefore, GammaPC is more accurate than space AR, and the GammaPC value where pattern collapse ratio begins to increase can be used to quantitatively determine the pattern collapse prevention performance of dry technologies. Figure 1

Multiplex Analysis on Phase Separation and Ion Conductivity at Bulks and Surfaces of Designed Anion Exchange Membranes

Anion exchange membrane fuel cells (AEMFCs) are attracting much attention because of the potential use of non-platinum catalysts. The hydroxide ion conductivity of the anion exchange membranes (AEMs) is still not sufficient, which is a drawback for the commercialization. To achieve higher performances of AEMFCs, understanding the nano-scale phase separations inside the membranes is essential. So far, only few results have been reported on the anion conducting behavior either inside the bulk or on the surface of AEMs.1,2) In this study, AEMs strategically designed with different chemical structures were systematically investigated by transmission electron microscopy (TEM) in vacuum and small angle X-ray scattering (SAXS) for the structures inside the bulk membranes on the nanometer scale, and by in-situcurrent-sensing atomic force microscopy (CS-AFM) with an environmental chamber for the morphology and the ion conductive region on the membrane surfaces. Fig. 1 shows the chemical structure of the QPE-bl-11 membrane synthesized in our laboratory.3) The membranes with the same chemical component but with different ion exchange capacities (IECs) of 1.23 (X = 4, m: n = 1:2.9) and 1.95 mequiv g−1 (X = 4, m: n = 1:5.4) were prepared in a chloride-ion form. Fig. 2 shows the SAXS profiles of the QPE-bl-11 membrane. For both membranes, the peak intensity increased with increasing humidity, which indicates the development of periodic structures. With 1.23 mequiv g-1 (Fig. 2(a)), weak and broad peaks were observed at the real-space distance (d) of ca. 17 nm. With 1.95 mequiv g-1 (Fig. 2(b), a peak at d = ca. 17 nm first observed at 30% RH became larger and located at d = ca. 18 nm at 90% RH. The peak intensity was larger with IEC =1.95 mequiv g-1 especially at higher humidities. For the CS-AFM measurements at 40 °C, the membrane was pressed on a gas-diffusion electrode (GDE) with a catalyst layer composed of Pt/C and a binder (AS-5, Tokuyama Corp.).2,4) Fig. 3 shows the current images on the two membranes. At 30% RH with IEC =1.23 mequiv g-1 (Fig. 3(a)), the tip current was always less than the detection limit of 0.5 pA in the scanned area of 1 μm x 1 μm. On the membrane with IEC =1.95 mequiv g-1 (Fig. 3(b)), the OH− conductive area covered nearly 100% of the surface. The average current was approximately 10 pA. Fig. 3(c) shows the current image with IEC =1.23 mequiv g-1 obtained at 70% RH. Anion conductive spots were observed over the surface unlike that at 30% RH. Still, the current ranged from 0 to 30 pA. With IEC =1.95 mequiv g-1at 70% RH (Fig. 3(d)), the anion conductive regions were observed over the surface and more homogeneous. The tip current was larger than 5 pA at any location with an average current of 15 pA. The different IECs gave not only quantitative but also qualitative influences on the membrane morphology and properties, and the differences became larger at higher relative humidity. In the presentation, the membranes with other structures will also be discussed. 1) Q. He and X. Ren, J. Power Sources, 220 (2012) 373. 2) M. Hara et al., Langmuir, 32 (2016) 9557. 3) R. Akiyama et al., Macromolecules, 49 (2016) 4480. 4) T. Kimura et al., J. Power Sources, submitted. Figure 1

Axion crystals

The low-energy effective theories for gapped insulators are classified by three parameters: permittivity ϵ, permeability μ, and theta angle θ. Crystals with periodic ϵ are known as photonic crystals. We here study the band structure of photons in a new type of crystals with periodic θ (modulo 2π) in space, which we call the axion crystals. We find that the axion crystals have a number of new properties that the usual photonic crystals do not possess, such as the helicity-dependent mass gap and nonrelativistic gapless dispersion relation at small momentum. We briefly discuss possible realizations of axion crystals in condensed matter systems and high-energy physics.

Line operators in the Standard Model

There is an ambiguity in the gauge group of the Standard Model. The group is G = SU(3) × SU(2) × U(1)/Γ, where Γ is a subgroup of Z6 which cannot be determined by current experiments. We describe how the electric, magnetic and dyonic line operators of the theory depend on the choice of Γ. We also explain how the periodicity of the theta angles, associated to each factor of G, differ.

CP as a Symmetry of Symmetries

It is explained that the Standard Model combined charge conjugation and parity transformation (CP) is a simultaneous complex conjugation outer automorphism transformation of gauge and space-time symmetries. Simple examples are given for the general concept of outer automorphisms (“symmetries of symmetries”), as well as for their possible actions on physical theories. It is highlighted that complex conjugation outer automorphisms do not, in general, exist for all symmetries. Examples are given for cases in which the physical CP transformation is violated as a consequence of requiring another symmetry. A toy model is illustrated in which CP is spontaneously violated in the broken phase of a continuous gauge symmetry, while an unbroken outer automorphism protects the topological vacuum angle at θ = 0.

Online Signature Recognition Based on Pseudo-Inked Signature Image Template

As human–robot interaction is widely and increasingly used, automated user verification has become a necessary condition for system access. Signature recognition is one of the representative methods for user verification. In this paper, a novel method using Pseudo-Inked Signature for online signature recognition is proposed. Pseudo-Inked Signature consists of three types of information of pen pressure value, pen tilting angle, and pen theta angle during online signature writing. We propose a fusion method for three different types of information by mimicking the inked effect of real pen writing. Besides a style of penmanship, Pseudo-Inked Signature reflects the characteristics of handwriting behavior. Therefore, it can make different Pseudo-Inked Signature even though the original signature images from different users look very similar to each other. Similarly, it can also make more similar Pseudo-Inked Signatures even though the original signature images from the same user look somewhat different to each other. In addition, since only one gray-scale image is dealt with to represent the signature style of a person by Pseudo-Inked Signature image, it is efficient and very easy to handle. Finally, we tested user verification experiments using [Formula: see text]-NN classifier. The experimental results show that Pseudo-Inked Signature is good enough for the real application.

(In)dependence of 𝜃 in the Higgs regime without axions

We revisit the issue of the vacuum angle [Formula: see text] dependence in weakly coupled (Higgsed) Yang–Mills theories. Two most popular mechanisms for eliminating physical [Formula: see text] dependence are massless quarks and axions. Anselm and Johansen noted that the vacuum angle [Formula: see text], associated with the electroweak SU(2) in the Glashow–Weinberg–Salam model (Standard Model, SM), is unobservable although all fermion fields obtain masses through Higgsing and there is no axion. We generalize this idea to a broad class of Higgsed Yang–Mills theories. In the second part, we consider the consequences of Grand Unification. We start from a unifying group, e.g. SU(5), at a high ultraviolet scale and evolve the theory down within the Wilson procedure. If on the way to infrared the unifying group is broken down into a few factors, all factor groups inherit one and the same [Formula: see text] angle — that of the unifying group. We show that embedding the SM in SU(5) drastically changes the Anselm–Johansen conclusion: the electroweak vacuum angle [Formula: see text], equal to [Formula: see text] becomes in principle observable in [Formula: see text] processes. We also note in passing that if the axion mechanism is set up above the unification scale, we have one and the same axion in the electroweak theory and QCD, and their impacts are interdependent.

A model study of present-day Hall-effect circulators

Stimulated by the recent implementation of a three-port Hall-effect microwave circulator of Mahoney et al. (MEA), we present model studies of the performance of this device. Our calculations are based on the capacitive-coupling model of Viola and DiVincenzo (VD). Based on conductance data from a typical Hall-bar device obtained from a two-dimensional electron gas (2DEG) in a magnetic field, we numerically solve the coupled field-circuit equations to calculate the expected performance of the circulator, as determined by the S parameters of the device when coupled to 50Ω ports, as a function of frequency and magnetic field. Above magnetic fields of 1.5 T, for which a typical 2DEG enters the quantum Hall regime (corresponding to a Landau-level filling fraction ν of 20), the Hall angle theta_{H}=tan^{-1}sigma_{xy}/sigma_{xx} always remains close to 90°, and the S parameters are close to the analytic predictions of VD for theta_{H}=pi/2. As anticipated by VD, MEA find the device to have rather high (kΩ) impedance, and thus to be extremely mismatched to 50Ω, requiring the use of impedance matching. We incorporate the lumped matching circuits of MEA in our modeling and confirm that they can produce excellent circulation, although confined to a very small bandwidth. We predict that this bandwidth is significantly improved by working at lower magnetic field when the Landau index is high, e.g. nu=20, and the impedance mismatch is correspondingly less extreme. Our modeling also confirms the observation of MEA that parasitic port-to-port capacitance can produce very interesting countercirculation effects.

Measurement of the W boson polarisation in tbar{t} events from pp collisions at sqrt{s} = 8 TeV in the lepton\xa0+\xa0jets channel with ATLAS

This paper presents a measurement of the polarisation of W bosons from tbar{t} decays, reconstructed in events with one high-p_{text{ T }} lepton and at least four jets. Data from pp collisions at the LHC were collected at sqrt{s} = 8 TeV and correspond to an integrated luminosity of 20.2 fb^{-1}. The angle theta ^{*} between the b-quark from the top quark decay and a direct W boson decay product in the W boson rest frame is sensitive to the W boson polarisation. Two different W decay products are used as polarisation analysers: the charged lepton and the down-type quark for the leptonically and hadronically decaying W boson, respectively. The most precise measurement of the W boson polarisation via the distribution of cos {theta ^{*}} is obtained using the leptonic analyser and events in which at least two of the jets are tagged as b-quark jets. The fitted fractions of longitudinal, left- and right-handed polarisation states are F_{mathrm {0}}=~0.709~pm ~{0.019}, F_{mathrm {L}}=~0.299~pm ~{0.015} and F_{mathrm {R}}=~-0.008~pm ~{0.014}, and are the most precisely measured W boson polarisation fractions to date. Limits on anomalous couplings of the Wtb vertex are set.

Aspects of Berry phase in QFT

When continuous parameters in a QFT are varied adiabatically, quantum states typically undergo mixing — a phenomenon characterized by the Berry phase. We initiate a systematic analysis of the Berry phase in QFT using standard quantum mechanics methods. We show that a non-trivial Berry phase appears in many familiar QFTs. We study a variety of examples including free electromagnetism with a theta angle, and certain supersymmetric QFTs in two and four spacetime dimensions. We also argue that a large class of QFTs with rich Berry properties is provided by CFTs with non-trivial conformal manifolds. Using the operator-state correspondence we demonstrate in this case that the Berry connection is equivalent to the connection on the conformal manifold derived previously in conformal perturbation theory. In the special case of chiral primary states in 2d mathcal{N}=left(2,2right) and 4d mathcal{N}=2 SCFTs the Berry phase is governed by the tt* equations. We present a technically useful rederivation of these equations using quantum mechanics methods.

Three-flavoured neutrino oscillations and the Leggett\u2013Garg inequality

Three-flavoured neutrino oscillations are investigated in the light of the Leggett–Garg inequality (LGI). The results obtained are: (a) The maximum violation of the LGI is 2.17036 for neutrino path length L_{1}=140.15 km and Delta L=1255.7 km. (b) The presence of the mixing angle theta _{13} enhances the maximum violation of LGI by 4.6%. (c) The currently known mass hierarchy parameter alpha = 0.0305 increases the maximum violation of LGI by 3.7%. (d) The presence of a CP-violating phase parameter enhances the maximum violation of LGI by 0.24%, thus providing an alternative indicator of CP violation in three-flavoured neutrino oscillations. The outline of an experimental proposal is suggested whereby the findings of this investigation may be verified.