The inclusion of the Gaussian-curvature term in the bulk of Polyakov-Kleinert string action renders new boundary terms and conditions by Gauss-Bonnet theorem. Within a leading approximation, the eigenmodes of smooth worldsheets and the free-energy of
a gas of open rigid strings appears to be altered at second order in the coupling by the topological term . In analogy to the topological $theta$ term, the Gauss-Bonnet term is introduced into the effective action with a complex coupling to implement signed energy shifts. We investigate the rigid color flux-sheets between two static color sources near the critical point in the light of the topologically induced shifts. The Yang-Mills lattice data of the potential of static quark-antiquark $Qbar{Q}$ in a heatbath is compared to the string potential. The Monte-Carlo data correspond to link-integrated Polyakov-loop correlators averaged over SU(3) gauge configurations at $beta=6.0$. Substantial improvement in the fit behavior is displayed over the nonperturbative source separation distance $0.2$ fm to $1.0$ fm. Remarkably, the returned coupling parameter of the topological term from the fit exhibits a proportionality to a quantum number. These findings suggest that the manifested modes are the winding number of a topological particle on the strings worldsheet.
We investigate the implications of Nambu-Goto (NG), Luscher-Weisz (LW) and Polyakov-Kleinert (PK) string actions for the Casimir energy of the QCD flux-tube at one and two loop order at finite temperature. We perform our numerical study on the 4-dim
pure SU(3) Yang-Mills lattice gauge theory at finite temperature $beta=6.0$. The static quark-antiquark potential is calculated using link-integrated Polyakov loop correlators. At a high temperature-close to the critical point- We find that the rigidity and self-interactions effects of the QCD string to become detectable. The remarkable feature of this model is that it retrieves a correct dependency of the renormalized string tension on the temperature. Good fit to static potential data at source separations $R ge 0.5$ fm is obtained when including additional two-boundary terms of (LW) action. On the other-hand, at a lower temperature-near the QCD plateau- We detect signatures of two boundary terms of the Luscher-Weisz (LW) string action. The (LW) string with boundary action is yielding a static potential which is in a good agreement with the lattice data, however, for color source separation as short as $R=0.3$ fm.
The width of the quantum delocalization of the QCD strings is investigated in effective string models beyond free Nambu-Goto approximation. We consider two Lorentzian-invariant boundary-terms in the Luscher-Weisz string action in addition to self-int
eraction term equivalent to two loop order in the (NG) string action. The geometrical terms which realize the possible rigidity of the QCD string is scrutinized as well. We perform the numerical analysis on the 4-dim pure $SU(3)$ Yang-Mills lattice gauge theory at two temperature scales near deconfinement point. The comparative study with this QCD string model targets the width of the energy profile of a static quark-antiquark system for color sources separation $0.5 le R le 1.2$ fm. We find the inclusion of rigidity properties and symmetry effects of the boundary action into the string paradigm to reproduce a good match with the profile of the Mont-Carlo data of QCD flux-tube on this distance scale.
The mean-square width of the energy profile of bosonic string is calculated considering two boundary terms in the effective action. The perturbative expansion of the Lorentz-invariant boundary terms at the second and the fourth order in the effective
action is taken around the free Nambu-Goto action. The calculation are presented for open strings with Dirichlet boundary condition on cylinder.
A robust power gating design using Graphene Nano-Ribbon Field Effect Transistors (GNRFET) is proposed using 16nm technology. The Power Gating (PG) structure is composed of GNRFET as a power switch and MOS power gated module. The proposed structure re
solves the main drawbacks of the traditional PG design from the point of view increasing the propagation delay and wake-up time in low voltage regions. GNRFET/MOSFET Conjunction (GMC) is employed to build various structures of PG, GMCPG-SS and GMCPG-NS. In addition to exploiting it to build two multi-mode PG structures. Circuit analysis for CMOS power gated logic modules ISCAS85 benchmark of 16nm technology is used to evaluate the performance of the proposed GNR power switch is compared to the traditional MOS one. Leakage power, wake-up time and power delay product are used as performance circuit parameters for the evaluation.
We present perturbative calculation of the width of the energy profile of rigid strings up to two loops in D dimensions. The perturbative expansion of the extrinsic curvature term signifying the rigidity/smoothness of the string in Polyakov-Kleinert
action is taken around the free Nambu-Goto string. The mean-square width of the string field is derived for open strings with Dirichlet boundary condition. We compare the broadening of the smooth Polyakov-Kleinert string to the lattice Mont-Carlo data of the QCD flux tube just before the deconfinement point and find a good match at the intermediate and large color source separation.
