scholarly journals STABLE CHROMOMAGNETIC QCD VACUUM AND CONFINEMENT

2010 ◽  
Vol 25 (30) ◽  
pp. 2591-2598 ◽  
Author(s):  
R. PARTHASARATHY
Keyword(s):  
Energy Density ◽  
Finite Temperature ◽  
Wilson Loop ◽  
Potential Model ◽  
Linear Potential ◽  
Effective Energy ◽  
Leading Order ◽  
Model Calculations ◽  
Yang Mills ◽  
Qcd Vacuum

The stable chromomagnetic vacuum for SU(2) Yang–Mills theory found earlier is shown to give a model for confinement in QCD, using Wilson loop and a linear potential (in the leading order) for quark–antiquark interaction. The coefficient k in this potential is found to be ~ 0.25 GeV2, in satisfactory agreement with nonrelativistic potential model calculations for charmonium. At finite temperature, the real effective energy density found earlier is used to obtain estimates of the deconfining temperature agreeing reasonably with lattice study for SU(2).

scholarly journals Fully Quantum String Representation of a Wilson Loop in the Finite-Temperature 3D Yang–Mills Theory

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 688
Author(s):  
Dmitry Antonov
Keyword(s):  
Critical Temperature ◽  
Finite Temperature ◽  
Wilson Loop ◽  
Conformal Anomaly ◽  
Yang Mills ◽  
Quantum Description ◽  
String Representation ◽  
Confinement Phase

We demonstrate the emergence of the Polchinski–Strominger term in the string representation of a Wilson loop in the confinement phase of the finite-temperature 3D Yang–Mills theory. At a temperature which is roughly twice smaller than the deconfinement critical temperature, the value of the coupling of that term becomes such that the string conformal anomaly cancels out, thereby admitting a fully quantum description of the quark–antiquark string in 3D rather than 26D.

SAVVIDY VACUUM IN SU(2) YANG–MILLS THEORY

2005 ◽  
Vol 20 (22) ◽  
pp. 1655-1662 ◽  
Author(s):  
DANIEL KAY ◽  
A. KUMAR ◽  
R. PARTHASARATHY
Keyword(s):  
Energy Density ◽  
Imaginary Part ◽  
Functional Integral ◽  
Quadratic Approximation ◽  
Effective Energy ◽  
The Real ◽  
Yang Mills ◽  
The One

The one-loop effective energy density of a pure SU (2) Yang–Mills theory in the Savvidy background is reconsidered. The stable and the unstable modes are identified. The stable modes are treated in the quadratic approximation. For the unstable modes, the full expansion including the cubic and the quartic terms in the fluctuations is used. The functional integral for the unstable modes is evaluated and added to the result for the stable modes. The resulting energy density coincides with the real part in the quadratic approximation of earlier studies and there is now no imaginary part.

CHIRAL QCD VACUUM ENERGY DENSITY IN THE ZERO MODES ENHANCEMENT QUANTUM MODEL

2000 ◽  
Vol 15 (01) ◽  
pp. 45-64 ◽  
Author(s):  
V. GOGOHIA ◽  
H. TOKI ◽  
T. SAKAI ◽  
Gy. KLUGE
Keyword(s):  
Energy Density ◽  
Vacuum Energy ◽  
Chiral Limit ◽  
Dyson Equation ◽  
Chiral Condensate ◽  
Vacuum Energy Density ◽  
Quantum Model ◽  
Yang Mills ◽  
Qcd Vacuum ◽  
Order Of Magnitude

Using the effective potential approach for composite operators we have formulated the quantum model of the QCD vacuum. It is based on the existence and importance of the nonperturbative q-4-type dynamical, topologically nontrivial excitations of the gluon field configurations (due to self-interaction of the massless gluons only). The QCD vacuum is found to be stable since the vacuum energy density has no imaginary part. The Yang–Mills (YM) part of the vacuum energy density is always negative and depends on a finite scale at which nonperturbative effects become important. The quark part of the vacuum energy density depends in addition on the constant of integration of the corresponding Schwinger–Dyson equation. The value of the above-mentioned scale is determined from the bounds for the pion decay constant in the chiral limit. Our value for the chiral QCD vacuum energy density is one order of magnitude bigger than the instanton based models can provide while a fair agreement with recent phenomenological and lattice results for the chiral condensate is obtained.

scholarly journals Symmetric Wilson Loops beyond leading order

2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Xinyi Chen-Lin
Keyword(s):  
Strong Coupling ◽  
Wilson Loop ◽  
Order Term ◽  
Exact Result ◽  
Wilson Loops ◽  
Leading Order ◽  
Fundamental Representation ◽  
Symmetric Representation ◽  
Yang Mills

We study the circular Wilson loop in the symmetric representation of U(N)U(N) in mathcal{N} = 4𝒩=4 super-Yang-Mills (SYM). In the large NN limit, we computed the exponentially-suppressed corrections for strong coupling, which suggests non-perturbative physics in the dual holographic theory. We also computed the next-to-leading order term in 1/N1/N, and the result matches with the exact result from the kk-fundamental representation.

scholarly journals Exact 1/N expansion of Wilson loop correlators in $$ \mathcal{N} $$ = 4 Super-Yang-Mills theory

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Wolfgang Mück
Keyword(s):  
Matrix Model ◽  
Wilson Loop ◽  
Model Solution ◽  
Wilson Loops ◽  
Combinatorial Formula ◽  
Expectation Value ◽  
Yang Mills ◽  
Hooft Coupling ◽  
The Matrix ◽  
Super Yang Mills Theory

Abstract Supersymmetric circular Wilson loops in $$ \mathcal{N} $$ N = 4 Super-Yang-Mills theory are discussed starting from their Gaussian matrix model representations. Previous results on the generating functions of Wilson loops are reviewed and extended to the more general case of two different loop contours, which is needed to discuss coincident loops with opposite orientations. A combinatorial formula representing the connected correlators of multiply wound Wilson loops in terms of the matrix model solution is derived. Two new results are obtained on the expectation value of the circular Wilson loop, the expansion of which into a series in 1/N and to all orders in the ’t Hooft coupling λ was derived by Drukker and Gross about twenty years ago. The connected correlators of two multiply wound Wilson loops with arbitrary winding numbers are calculated as a series in 1/N. The coefficient functions are derived not only as power series in λ, but also to all orders in λ by expressing them in terms of the coefficients of the Drukker and Gross series. This provides an efficient way to calculate the 1/N series, which can probably be generalized to higher-point correlators.

scholarly journals Entanglement entropy for $$ \mathrm{T}\overline{\mathrm{T}} $$, $$ \mathrm{J}\overline{\mathrm{T}} $$, $$ \mathrm{T}\overline{\mathrm{J}} $$ deformed holographic CFT

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Soumangsu Chakraborty ◽  
Akikazu Hashimoto
Keyword(s):  
Parameter Space ◽  
Wilson Loop ◽  
Lorentz Invariance ◽  
Entanglement Entropy ◽  
Geodesic Equation ◽  
Leading Order ◽  
Theoretic Analysis ◽  
Expectation Value ◽  
Spatial Coordinates ◽  
Single Trace

Abstract We derive the geodesic equation for determining the Ryu-Takayanagi surface in AdS3 deformed by single trace $$ \mu T\overline{T} $$ μT T ¯ + $$ {\varepsilon}_{+}J\overline{T} $$ ε + J T ¯ + $$ {\varepsilon}_{-}T\overline{J} $$ ε − T J ¯ deformation for generic values of (μ, ε+, ε−) for which the background is free of singularities. For generic values of ε±, Lorentz invariance is broken, and the Ryu-Takayanagi surface embeds non-trivially in time as well as spatial coordinates. We solve the geodesic equation and characterize the UV and IR behavior of the entanglement entropy and the Casini-Huerta c-function. We comment on various features of these observables in the (μ, ε+, ε−) parameter space. We discuss the matching at leading order in small (μ, ε+, ε−) expansion of the entanglement entropy between the single trace deformed holographic system and a class of double trace deformed theories where a strictly field theoretic analysis is possible. We also comment on expectation value of a large rectangular Wilson loop-like observable.

BOUNDS ON f(G) GRAVITY FROM ENERGY CONDITIONS

2010 ◽  
Vol 25 (27) ◽  
pp. 2325-2332 ◽  
Author(s):  
PUXUN WU ◽  
HONGWEI YU
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Energy Density ◽  
Modified Gravity ◽  
Energy Conditions ◽  
Model Parameters ◽  
Effective Energy ◽  
Raychaudhuri Equation ◽  
Accelerating Expansion

The f(G) gravity is a theory to modify the general relativity and it can explain the present cosmic accelerating expansion without the need of dark energy. In this paper the f(G) gravity is tested with the energy conditions. Using the Raychaudhuri equation along with the requirement that the gravity is attractive in the FRW background, we obtain the bounds on f(G) from the SEC and NEC. These bounds can also be found directly from the SEC and NEC within the general relativity context by the transformations: ρ → ρm + ρE and p → pm + pE, where ρE and pE are the effective energy density and pressure in the modified gravity. With these transformations, the constraints on f(G) from the WEC and DEC are obtained. Finally, we examine two concrete examples with WEC and obtain the allowed region of model parameters.

scholarly journals Potential model calculations and predictions forcs¯quarkonia

2009 ◽  
Vol 80 (3) ◽  
Author(s):  
Stanley F. Radford ◽  
Wayne W. Repko ◽  
Michael J. Saelim
Keyword(s):  
Potential Model ◽  
Model Calculations

Linear bounded potential model for semiconductor band bending

2022 ◽  
Author(s):  
Facundo Villavicencio ◽  
Jorge Mario Ferreyra ◽  
German Bridoux ◽  
Manuel Villafuerte
Keyword(s):  
Potential Model ◽  
Simple Expression ◽  
Linear Potential ◽  
Charge Balance ◽  
Band Bending ◽  
Mass Approximation ◽  
Hole Confinement ◽  
Dimensional Electron Gas ◽  
Analytical Expressions ◽  
Franz Keldysh Effect

Abstract We propose a simple but unexplored model for the semiconductor band bending with the aim to obtain a relatively simple expression to calculate the energy spectrum for the confined levels and the analytical expressions for wave-functions. This model consists of a linear potential but it is bounded or trimmed in energy unlike the well known wedge potential model. We present exact solutions for this potential in the frame of the effective mass approximation and they are valid for electron or hole confinement potential. This model provides a more adequate physical scenario than the wedge potential since it takes into account the charge balance involved in the band bending potential. These results allow to treat confined potential problems as in the case of a two-dimensional electron gas (2DEG) in a simplified way. We discuss the application of this approximation to the recombination time of electrons an holes and for the Franz-Keldysh effect.

INTERACTION EFFECT BETWEEN BEAM DIAMETER AND ENERGY DENSITY IN LASER-INDUCED TACTILE PERCEPTION

2018 ◽  
Vol 18 (07) ◽  
pp. 1840011
Author(s):  
MI-HYUN CHOI ◽  
HYUNG-SIK KIM ◽  
JI-HUN JO ◽  
JI-SUN KIM ◽  
JAE-HOON JUN ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Energy Density ◽  
Penetration Depth ◽  
Interaction Effect ◽  
Laser Energy ◽  
Tactile Sensation ◽  
Beam Diameter ◽  
Effective Energy ◽  
Effective Energy Transfer ◽  
Response Phase

This study aims to investigate the interaction effect between the beam diameter and energy density, which are perceived as laser-induced tactile perception by humans, by diversely varying the laser parameters, beam diameter, and energy. Eight healthy male college students of 23.5[Formula: see text][Formula: see text][Formula: see text]1.7 years participated in the study. The range of the beam diameter of the displayed laser stimulation was between 0.03[Formula: see text]mm and 8[Formula: see text]mm, and a total of 21 sizes were displayed. The laser energy was sequentially displayed from the minimum energy that can be displayed by one beam diameter to the maximum energy range that does not exceed the maximum permissible exposure (MPE) level since the energy varies according to the beam diameter. The laser energy was controlled by an optical density ([Formula: see text]) filter and was measured by an optical power meter (energy meter). Furthermore, the beam diameter was adjusted by moving the lens, which was confirmed with the beam profiler. The experimental test consists of the control phase (19[Formula: see text]s), stimulus phase (7[Formula: see text]s), and response phase (4[Formula: see text]s); the total duration of the test was 30[Formula: see text]s. The stimulus phase is the period in which stimulation was displayed on the skin through laser irradiation, and the stimulation was displayed by changing the beam diameter and the energy from the laser. The total number of beam diameter and energy pairs displayed to the subjects was 113 and 5 trials of irradiation were conducted for each pair. Stimulation perception response was recorded by pressing the response buttons during the response phase, and the responses were predefined as “no feeling,” “tactile sensation”, and “pain.” Through the extracted response data from the response phase, the beam diameter and energy density pair in which more than 50% of the subjects responded as having perceived tactile sensation were selected from the possible laser energy that could be displayed from one beam diameter. The simulation results showed that increasing the beam diameter increased the penetration depth, indicating an effective energy transfer to the skin. Therefore, increasing the beam diameter results in increased scattering, and hence increased penetration depth, and ultimately a more effective energy transfer. Therefore, increased beam diameter results in higher energy transfer efficiency, indicating that the required energy density by more than 50% of the subjects to perceive tactile sensation decreased.

Sign in / Sign up

Export Citation Format

Share Document