scholarly journals Misaligned supersymmetry and open strings

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Niccolò Cribiori ◽  
Susha Parameswaran ◽  
Flavio Tonioni ◽  
Timm Wrase
Keyword(s):  
String Theory ◽  
Energy Levels ◽  
Closed String ◽  
Type Ii ◽  
Open Strings ◽  
String Landscape ◽  
String Theories

Abstract The study of non-supersymmetric string theories is shedding light on an important corner of the string landscape and might ultimately explain why, so far, we did not observe supersymmetry in our universe. We review how misaligned supersymmetry in closed-string theories leads to a cancellation between bosons and fermions even in non-supersymmetric string theories. We then show that the same cancellation takes place for open strings by studying an anti-Dp-brane placed on top of an Op-plane in type II string theory. Misaligned supersymmetry consists in cancellations between bosons and fermions at different energy levels, in such a way that the averaged number of states grows at a rate dominated by a factor $$ {\mathrm{e}}^{C_{\mathrm{e}\mathrm{ff}}\sqrt{n}} $$ e C eff n , with Ceff< Ctot, where Ctot is the inverse Hagedorn temperature. We prove the previously conjectured complete cancellation, i.e. we prove that Ceff = 0, for a vast class of models.

scholarly journals TWO-DIMENSIONAL YANG-MILLS THEORIES ARE STRING THEORIES

1993 ◽  
Vol 08 (23) ◽  
pp. 2223-2235 ◽  
Author(s):  
STEPHEN G. NACULICH ◽  
HAROLD A. RIGGS ◽  
HOWARD J. SCHNITZER
Keyword(s):  
String Theory ◽  
Partition Function ◽  
Arbitrary Number ◽  
Closed String ◽  
Two Dimensional ◽  
Branched Covers ◽  
Yang Mills ◽  
String Worldsheet ◽  
String Theories

We show that two-dimensional SO (N) and Sp (N) Yang-Mills theories without fermions can be interpreted as closed string theories. The terms in the 1/N expansion of the partition function on an orientable or nonorientable manifold ℳ can be associated with maps from a string worldsheet onto ℳ. These maps are unbranched and branched covers of ℳ with an arbitrary number of infinitesimal worldsheet cross-caps mapped to points in ℳ. These string theories differ from SU (N) Yang-Mills string theory in that they involve odd powers of 1/N and require both orientable and nonorientable worldsheets.

TORUS-ORBIFOLD EQUIVALENCE IN COMPACTIFIED STRING THEORIES

1990 ◽  
Vol 05 (14) ◽  
pp. 1131-1145 ◽  
Author(s):  
MAKOTO SAKAMOTO
Keyword(s):  
Gauge Symmetry ◽  
String Theory ◽  
Closed String ◽  
String Theories

It is shown that any compactified closed string theory on an abelian orbifold is equivalent to that on a torus if the rank of the gauge symmetry of strings on the orbifold is equal to the dimension of the orbifold. Our proof clarifies the correspondence operators as well as states between the two theories.

scholarly journals Entanglement entropy and edge modes in topological string theory. Part I. Generalized entropy for closed strings

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
William Donnelly ◽  
Yikun Jiang ◽  
Manki Kim ◽  
Gabriel Wong
Keyword(s):  
Hilbert Space ◽  
String Theory ◽  
Entanglement Entropy ◽  
Topological String ◽  
Closed String ◽  
Simons Theory ◽  
Topological String Theory ◽  
Open Strings ◽  
Reduced Density ◽  
Theory Calculation

Abstract Progress in identifying the bulk microstate interpretation of the Ryu-Takayanagi formula requires understanding how to define entanglement entropy in the bulk closed string theory. Unfortunately, entanglement and Hilbert space factorization remains poorly understood in string theory. As a toy model for AdS/CFT, we study the entanglement entropy of closed strings in the topological A-model in the context of Gopakumar-Vafa duality. We will present our results in two separate papers. In this work, we consider the bulk closed string theory on the resolved conifold and give a self-consistent factorization of the closed string Hilbert space using extended TQFT methods. We incorporate our factorization map into a Frobenius algebra describing the fusion and splitting of Calabi-Yau manifolds, and find string edge modes transforming under a q-deformed surface symmetry group. We define a string theory analogue of the Hartle-Hawking state and give a canonical calculation of its entanglement entropy from the reduced density matrix. Our result matches with the geometrical replica trick calculation on the resolved conifold, as well as a dual Chern-Simons theory calculation which will appear in our next paper [1]. We find a realization of the Susskind-Uglum proposal identifying the entanglement entropy of closed strings with the thermal entropy of open strings ending on entanglement branes. We also comment on the BPS microstate counting of the entanglement entropy. Finally we relate the nonlocal aspects of our factorization map to analogous phenomenon recently found in JT gravity.

scholarly journals From Type II string theory toward BSM/dark sector physics

2016 ◽  
Vol 31 (34) ◽  
pp. 1630050 ◽  
Author(s):  
Gabriele Honecker
Keyword(s):  
String Theory ◽  
Open String ◽  
New Physics ◽  
Closed String ◽  
Type Ii ◽  
Dark Sector ◽  
Four Dimensions ◽  
Brane Model ◽  
Moduli Stabilization ◽  
String Compactifications

Four-dimensional compactifications of string theory provide a controlled set of possible gauge representations accounting for BSM particles and dark sector components. In this review, constraints from perturbative Type II string compactifications in the geometric regime are discussed in detail and then compared to results from heterotic string compactifications and nonperturbative/nongeometric corners. As a prominent example, an open string realization of the QCD axion is presented. The status of deriving the associated low-energy effective action in four dimensions is discussed and open avenues of major phenomenological importance are highlighted. As examples, a mechanism of closed string moduli stabilization by D-brane backreaction as well as one-loop threshold corrections to the gauge couplings and balancing a low string scale [Formula: see text] with unisotropic compact dimensions are discussed together with implications on potential future new physics observations. For illustrative purposes, an explicit example of a globally consistent D6-brane model with MSSM-like spectrum on [Formula: see text] is presented.

OPEN STRINGS AS Z2-ORBIFOLDS OF CLOSED STRINGS

1991 ◽  
Vol 06 (27) ◽  
pp. 2483-2496
Author(s):  
GREG NAGAO
Keyword(s):  
Open String ◽  
Closed String ◽  
Bosonic String ◽  
Modular Invariant ◽  
Open Strings ◽  
Loop Expansion ◽  
Invariant Formulation ◽  
Closed Bosonic String ◽  
String Theories

We present a modular invariant formulation of the open string in terms of the closed string. Chan–Paton factors are understood as multiplicities which arise from a factorization of the closed string. This interpretation of the Chan–Paton factors suggests that the SO (2D/2) open string is consistent to all orders of the loop expansion. We show that the open string may be viewed as a Z2-orbifold of the closed string. Relations are found between various string theories which seem to reinforce an earlier suggestion by Freund that all string theories are derivable from the D = 26 orientable closed bosonic string.

scholarly journals Comments on D3-brane holography

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Soumangsu Chakraborty ◽  
Amit Giveon ◽  
David Kutasov
Keyword(s):  
String Theory ◽  
Quantum Dynamics ◽  
Closed String ◽  
Asymptotically Flat ◽  
Hooft Coupling ◽  
Flat Spacetime ◽  
Open Strings

Abstract We revisit the idea that the quantum dynamics of open strings ending on N D3-branes in the large N limit can be described at large ‘t Hooft coupling by classical closed string theory in the background created by the D3-branes in asymptotically flat spacetime. We study the resulting thermodynamics and compute the Hagedorn temperature and other properties of the D3-brane worldvolume theory in this regime. We also consider the theory in which the D3-branes are replaced by negative branes and show that its thermodynamics is well behaved. We comment on the idea that this theory can be thought of as an irrelevant deformation of $$ \mathcal{N} $$ N = 4 SYM, and on its relation to $$ T\overline{T} $$ T T ¯ deformed CFT2.

scholarly journals BRANE SOLUTIONS IN TIME-DEPENDENT BACKGROUNDS IN D = 11 SUPERGRAVITY AND IN TYPE II STRING THEORIES

2008 ◽  
Vol 23 (16n17) ◽  
pp. 2525-2540 ◽  
Author(s):  
SRIKUMAR SEN GUPTA
Keyword(s):  
String Theory ◽  
Equations Of Motion ◽  
Space Time ◽  
Time Dependent ◽  
Type Ii ◽  
Reduced Equations ◽  
Special Cases ◽  
M Theory ◽  
String Theories

We obtain explicit time-dependent brane solutions in M-theory as well as in string theory by solving the reduced equations of motion (which follow, as in Int. J. Mod. Phys. A17, 4647 (2002), from 11-dimensional supergravity) for a class of brane solutions in curved backgrounds. The behavior of our solutions in both asymptotic and near-horizon limits are studied. It is shown that our time-dependent solutions serve as explicit examples of branes in singular, cosmological backgrounds. In some special cases the asymptotic and the boundary AdS solutions can be identified as Milne × Rn space–time.

scholarly journals LOOP VARIABLES AND GAUGE INVARIANT EXACT RENORMALIZATION GROUP EQUATIONS FOR CLOSED STRING THEORY

2013 ◽  
Vol 28 (24) ◽  
pp. 1350116 ◽  
Author(s):  
B. SATHIAPALAN
Keyword(s):  
Renormalization Group ◽  
String Theory ◽  
Open String ◽  
Background Field ◽  
Closed String ◽  
Gauge Transformations ◽  
Open Strings ◽  
Field Formalism ◽  
Exact Renormalization Group

We formulate the Exact Renormalization Group on the string worldsheet for closed string backgrounds. The same techniques that were used for open strings are used here. There are some subtleties. One is that holomorphic factorization of the closed string vertex operators does not hold in the presence of a cutoff on the Euclidean worldsheet. This introduces extra terms in the Lagrangian at the cutoff scale and they turn out to be crucial for implementing gauge invariance. This naive generalization from open string to closed string requires a massive graviton and the gauge symmetry is Abelian, just as in open string theory. Interestingly, it turns out that if one introduces a nondynamical background metric (as in background field formalism) and combines a gauge transformation on the field with a transformation on the coordinates and background metric, the graviton can be massless. Some examples of background coordinate covariant equations are worked out explicitly. A preliminary discussion of massive modes, massive gauge transformations and the role of worldsheet regulator terms is given. Some of the gauge transformations can be given a geometric meaning if space–time is assumed to be complex at some level.

scholarly journals Surface defects from fractional branes. Part II

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
S.K. Ashok ◽  
M. Billò ◽  
M. Frau ◽  
A. Lerda ◽  
S. Mahato
Keyword(s):  
String Theory ◽  
Surface Defect ◽  
Surface Defects ◽  
Closed String ◽  
Brane World ◽  
Type Ii ◽  
Yang Mills ◽  
Background Values ◽  
World Volume ◽  
Set Up

Abstract A generic half-BPS surface defect of $$ \mathcal{N} $$ N = 4 supersymmetric U(N ) Yang- Mills theory is described by a partition of N = n1 + . . . + nM and a set of 4M continuous parameters. We show that such a defect can be realized by nI stacks of fractional D3-branes in Type II B string theory on a ℤM orbifold background in which the brane world-volume is partially extended along the orbifold directions. In this set up we show that the 4M continuous parameters correspond to constant background values of certain twisted closed string scalars of the orbifold. These results extend and generalize what we have presented for the simple defects in a previous paper.

scholarly journals SO(3)×U(1) Isometric Instantons with Non-Abelian Hair in Four-Dimensional String Theory

1997 ◽  
Vol 12 (25) ◽  
pp. 1847-1858
Author(s):  
Adrián R. Lugo
Keyword(s):  
String Theory ◽  
Type Ii ◽  
Dimensional Solution ◽  
Coset Model

We compute the exact effective string vacuum backgrounds of the level k=81/19 SU(2,1)/U(1) coset model. A compact SU(2) isometry present in this seven-dimensional solution allows one to interpret it after compactification as a four-dimensional non-Abelian SU(2) charged instanton with a singular submanifold and an SO(3) × U(1) isometry. The semiclassical backgrounds, solutions of the type II strings, present similar characteristics

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