GAUGE MODELS OF FERMIONIC DISCRETE "STRINGS"

1990 ◽  
Vol 05 (05) ◽  
pp. 325-335 ◽  
Author(s):  
A.T. FILIPPOV ◽  
A.P. ISAEV
Keyword(s):  
String Theory ◽  
Finite Number ◽  
Degrees Of Freedom ◽  
Independent Variables ◽  
Gauge Models ◽  
New Class ◽  
Constrained Hamiltonian Systems ◽  
New Models ◽  
Fermionic String ◽  
Left And Right

A new class of constrained hamiltonian systems with a finite number of bosonic and fermionic degrees of freedom is proposed. Coordinates of these systems are divided into two groups of independent variables analogous to the left and right movers of the standard closed fermionic string theory. Hamiltonians are obtained by gauging some subgroups of the linear supercanonical transformations for the left and right variables. It is argued that some of the new models can be regarded as discrete analogs of the standard fermionic string theory. The extension of the models obtained by adding ghost variables is also constructed as a prerequisite to quantizing them.

GAUGE MODELS OF “DISCRETE STRINGS”

1989 ◽  
Vol 04 (22) ◽  
pp. 2167-2176 ◽  
Author(s):  
A.T. FILIPPOV ◽  
A.P. ISAEV
Keyword(s):  
Degrees Of Freedom ◽  
Supersymmetric Extension ◽  
Infinite Dimensional ◽  
Gauge Models ◽  
New Class ◽  
Integral Methods ◽  
Constrained Hamiltonian Systems ◽  
Left And Right ◽  
Constraint Algebra ◽  
The Continuum

A new class of constrained hamiltonian systems with a finite number of degrees of freedom is proposed in which excitations can be divided into two groups analogous to the left and right movers of string theories. Some of these models can be regarded as discrete analogs of the bosonic string, and in the continuum limit with the infinite dimensional constraint algebra Vect (S1)⊗ Vect (S1) one can obtain the classical theory of closed bosonic strings. We also discuss the problem of quantizing these models and constructing the propagator by using path integral methods. A possibility of a supersymmetric extension of our models is also pointed out.

scholarly journals Crisis on infinite earths: short-lived de Sitter vacua in the string theory landscape

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Heliudson Bernardo ◽  
Suddhasattwa Brahma ◽  
Keshav Dasgupta ◽  
Radu Tatar
Keyword(s):  
String Theory ◽  
Decay Time ◽  
Degrees Of Freedom ◽  
De Sitter ◽  
New Class ◽  
De Sitter Vacua

Abstract We construct purely non-perturbative anti-de Sitter vacua in string theory which, on uplifting to a de Sitter (dS) one, have a decay time many orders of magnitude smaller than those of standard constructions, such as the KKLT and LVS scenarios. By virtue of being constructed purely from non-perturbative terms, these vacua avoids certain obstructions plaguing other constructions of dS in string theory. This results in a new class of phenomenological dS vacua in string theory with novel distinctive characteristics such as having two maxima. After examining whether these uplifted dS vacua obey the TCC, we revisit some old problems of realization of dS space as a vacuum. We find that not only is it phenomenologically hard to construct TCC-compatible vacua, but also inherent temporal dependences of the degrees of freedom generically arise in such constructions, amongst other issues. This reinforces the idea that dS, if it exists in string theory, should be a Glauber-Sudarshan state and not a vacuum.

QUANTUM DISCRETE GAUGE MODELS WITH BOSONIC AND FERMIONIC DEGREES OF FREEDOM

1992 ◽  
Vol 07 (11) ◽  
pp. 2487-2507 ◽  
Author(s):  
A. T. FILIPPOV ◽  
D. GANGOPADHYAY ◽  
A. P. ISAEV
Keyword(s):  
Finite Number ◽  
Degrees Of Freedom ◽  
Discrete Models ◽  
Field Theories ◽  
Gauge Models ◽  
Dimensional Matrix

A general approach to quantizing discrete models (i.e. having a finite number of coordinates) with quadratic first-class constraints is presented in the framework of gauging linear canonical symmetries. Also, it is proposed how a natural superextension of matrix field theories (viz. orthosymplectic "zero-dimensional" matrix field theories) might emerge in this approach.

scholarly journals On an alternative quantization of R-NS strings

2021 ◽  
pp. 2130016
Author(s):  
Tsubasa Yuki ◽  
Yu Nakayama
Keyword(s):  
String Theory ◽  
Finite Number ◽  
Degrees Of Freedom ◽  
Superstring Theory ◽  
The Right ◽  
Creation Operators

We investigate an alternative quantization of R-NS string theory. In the alternative quantization, we define the distinct vacuum for the left-moving mode and the right-moving mode by exchanging the role of creation operators and annihilation operators in the left-moving sector. The resulting string theory has only a finite number of propagating degrees of freedom. We show that an appropriate choice of the GSO projection makes the theory tachyon free. The spectrum coincides with the massless sector of type IIA or type IIB superstring theory without any massive excitations.

The inverse problem of recovering the coefficients of a differential equations on a graph

2020 ◽  
Vol 28 (5) ◽  
pp. 727-738
Author(s):  
Victor Sadovnichii ◽  
Yaudat Talgatovich Sultanaev ◽  
Azamat Akhtyamov
Keyword(s):  
Inverse Problem ◽  
Inverse Problems ◽  
Differential Equations ◽  
Boundary Value Problem ◽  
Boundary Conditions ◽  
Finite Number ◽  
Characteristic Equation ◽  
Arbitrary Number ◽  
New Class ◽  
Finite Set

AbstractWe consider a new class of inverse problems on the recovery of the coefficients of differential equations from a finite set of eigenvalues of a boundary value problem with unseparated boundary conditions. A finite number of eigenvalues is possible only for problems in which the roots of the characteristic equation are multiple. The article describes solutions to such a problem for equations of the second, third, and fourth orders on a graph with three, four, and five edges. The inverse problem with an arbitrary number of edges is solved similarly.

scholarly journals A novel class of translationally invariant spin chains with long-range interactions

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
B. Basu-Mallick ◽  
F. Finkel ◽  
A. González-López
Keyword(s):  
Long Range ◽  
Degrees Of Freedom ◽  
Spin Chains ◽  
Open Chain ◽  
New Class ◽  
Spin Interactions ◽  
Long Range Interactions ◽  
Spin Reversal ◽  
Twisted Yangian ◽  
Internal Degrees Of Freedom

Abstract We introduce a new class of open, translationally invariant spin chains with long-range interactions depending on both spin permutation and (polarized) spin reversal operators, which includes the Haldane-Shastry chain as a particular degenerate case. The new class is characterized by the fact that the Hamiltonian is invariant under “twisted” translations, combining an ordinary translation with a spin flip at one end of the chain. It includes a remarkable model with elliptic spin-spin interactions, smoothly interpolating between the XXX Heisenberg model with anti-periodic boundary conditions and a new open chain with sites uniformly spaced on a half-circle and interactions inversely proportional to the square of the distance between the spins. We are able to compute in closed form the partition function of the latter chain, thereby obtaining a complete description of its spectrum in terms of a pair of independent su(1|1) and su(m/2) motifs when the number m of internal degrees of freedom is even. This implies that the even m model is invariant under the direct sum of the Yangians Y (gl(1|1)) and Y (gl(0|m/2)). We also analyze several statistical properties of the new chain’s spectrum. In particular, we show that it is highly degenerate, which strongly suggests the existence of an underlying (twisted) Yangian symmetry also for odd m.

scholarly journals Standard model from a supergravity model with a naturally small cosmological constant

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Shing Yan Li ◽  
Yu-Cheng Qiu ◽  
S.-H. Henry Tye
Keyword(s):  
String Theory ◽  
Standard Model ◽  
Cosmological Constant ◽  
Supersymmetry Breaking ◽  
Supersymmetric Standard Model ◽  
Degrees Of Freedom ◽  
Interaction Terms ◽  
Supersymmetric Version ◽  
The Standard Model ◽  
Linear Version

Abstract Guided by the naturalness criterion for an exponentially small cosmological constant, we present a string theory motivated 4-dimensional $$ \mathcal{N} $$ N = 1 non-linear supergravity model (or its linear version with a nilpotent superfield) with spontaneous supersymmetry breaking. The model encompasses the minimal supersymmetric standard model, the racetrack Kähler uplift, and the KKLT anti-D3-branes, and use the nilpotent superfield to project out the undesirable interaction terms as well as the unwanted degrees of freedom to end up with the standard model (not the supersymmetric version) of strong and electroweak interactions.

scholarly journals Lowering the scale of Pati-Salam breaking through seesaw mixing

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Matthew J. Dolan ◽  
Tomasz P. Dutka ◽  
Raymond R. Volkas
Keyword(s):  
Degrees Of Freedom ◽  
Tree Level ◽  
Charged Current ◽  
Meson Decay ◽  
Neutrino Masses ◽  
Down Quark ◽  
The Standard Model ◽  
Decay Widths ◽  
Left And Right ◽  
Charged Leptons

Abstract We analyse the experimental limits on the breaking scale of Pati-Salam extensions of the Standard Model. These arise from the experimental limits on rare-meson decay processes mediated at tree-level by the vector leptoquark in the model. This leptoquark ordinarily couples to both left- and right-handed SM fermions and therefore the meson decays do not experience a helicity suppression. We find that the current limits vary from $$ \mathcal{O} $$ O (80–2500) TeV depending on the choice of matrix structure appearing in the relevant three-generational charged-current interactions. We extensively analyse scenarios where additional fermionic degrees of freedom are introduced, transforming as complete Pati-Salam multiplets. These can lower the scales of Pati-Salam breaking through mass-mixing within the charged-lepton and down-quark sectors, leading to a helicity suppression of the meson decay widths which constrain Pati-Salam breaking. We find four multiplets with varying degrees of viability for this purpose: an SU(2)L/R bidoublet, a pair of SU(4) decuplets and either an SU(2)L or SU(2)R triplet all of which contain heavy exotic versions of the SM charged leptons. We find that the Pati-Salam limits can be as low as $$ \mathcal{O} $$ O (5–150) TeV with the addition of these four multiplets. We also identify an interesting possible connection between the smallness of the neutrino masses and a helicity suppression of the Pati-Salam limits for three of the four multiplets.

Choice and privatisation in Swedish primary care

2010 ◽  
Vol 6 (4) ◽  
pp. 549-569 ◽  
Author(s):  
Anders Anell
Keyword(s):  
Primary Care ◽  
Clinical Practice ◽  
Financial Incentives ◽  
Degrees Of Freedom ◽  
New Wave ◽  
Improve Performance ◽  
Financial Responsibility ◽  
New Models ◽  
Financial Characteristics

AbstractIn 2007, a new wave of local reforms involving choice for the population and privatisation of providers was initiated in Swedish primary care. Important objectives behind reforms were to strengthen the role of primary care and to improve performance in terms of access and responsiveness. The purpose of this article was to compare the characteristics of the new models and to discuss changes in financial incentives for providers and challenges regarding governance from the part of county councils. A majority of the models being introduced across the 21 county councils can best be described as innovative combinations between a comprehensive responsibility for providers and significant degrees of freedom regarding choice for the population. Key financial characteristics of fixed payment and comprehensive financial responsibility for providers may create financial incentives to under-provide care. Informed choices by the population, in combination with reasonably low barriers for providers to enter the primary care market, should theoretically counterbalance such incentives. To facilitate such competition is indeed a challenge, not only because of difficulties in implementing informed choices but also because the new models favour large and/or horizontally integrated providers. To prevent monopolistic behaviour, county councils may have to accept more competition as well as more governance over clinical practice than initially intended.

Study of some rheological models with a finite number of degrees of freedom

2000 ◽  
Vol 19 (2) ◽  
pp. 277-307 ◽  
Author(s):  
Jérôme Bastien ◽  
Michelle Schatzman ◽  
Claude-Henri Lamarque
Keyword(s):  
Finite Number ◽  
Degrees Of Freedom ◽  
Rheological Models
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