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Seungjoon Hyun

Publications and source records attributed to Seungjoon Hyun.

At least 55 records · Page 3Linked to original sources
arXiv2002

Branes from Matrix Theory in PP-Wave Background

Based on the recently proposed action for Matrix theory describing the DLCQ M theory in the maximally supersymmetric pp-wave background, we obtain the supersymmetry algebra of supercharge density. Using supersymmetry transformation rules for fermions, we identify BPS states with the central charges in the supersymmetry algebra, which can be activated only in the large N limit. They preserve some fraction of supersymmetries and correspond to rotating transverse membranes and longitudinal five branes.

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arXiv2002

Dynamical Aspects on Duality between SYM and NCOS from D2-F1 Bound State

It has been shown that (2+1)-dimensional N=8 super Yang-Mills (SYM) theory with electric flux is related to (2+1)- dimensional noncommutative open string (NCOS) theory by `2-11' flip. This implies that the instanton process in SYM theory, which corresponds to D0-brane exchange (M-momentum transfer) between D2-branes, is dual to the KK momentum exchange in NCOS theory, which is perturbative process in nature. In order to confirm this, we obtain the effective action of probe M2-brane on the background of tilted M2-branes, which would correspond to the one-loop effective action of SYM theory with non-perturbative instanton corrections. Then we consider the dual process in NCOS theory, which is the scattering amplitude of the wound graviton off the D2-F1 bound state involving KK-momentum transfer in x^2-direction. Both of them give the same interaction terms. Remarkably they also have the same behavior on the nontrivial velocity dependence. All these strongly support the duality between those two theories with completely different nature.

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arXiv2002

On Decoupling of Massless Modes in NCOS Theories

We revisit the decoupling phenomenon of massless modes in the noncommutative open string (NCOS) theories. We check the decoupling by explicit computation in (2+1) or higher dimensional NCOS theories and recapitulate the validity of the decoupling to all orders in perturbation theory.

hep-th↗
arXiv2001

Supersymmetry of Green-Schwarz Superstring and Matrix String Theory

We study the dynamics of Green-Schwarz superstring on the gravitational wave background corresponding to the Matrix string theory and the supersymmetry transformation rules of the superstring. The dynamics is obtained in the light-cone formulation and is shown to agree with that derived from the Matrix string theory. The supersymmetry structure has the corrections due to the effect of the background and is identified with that of the low energy one-loop effective action of Matrix string theory in two superstring background in the weak string coupling limit.

hep-th↗
arXiv2000

U-duality Between NCOS Theory and Matrix Theory

We show that the NCOS (noncommutative open string) theories on torus $T^p$ ($p\leq 5$) are U-dual to matrix theory on torus with electric flux background. Under U-duality, the number of D-branes and the number of units of electric flux get interchanged. Furthermore under the same U-duality the decoupling limit taken in the NCOS theory maps to the decoupling limit taken in the matrix theory, thus ensure the U-duality between those two class of theories. We consider the energy needed for Higgsing process and some bound states with finite energy and find agreements in both theories.

hep-th↗
arXiv2000

Conifolds with Discrete Torsion and Noncommutativity

We study D3 branes at orbifolded conifold singularities in the presence of discrete torsion. The vacuum moduli space of open strings becomes non-commutative due to a deformation of the superpotential and is studied via the representation theory of the moduli algebra. It is also shown that the center of the moduli algebra correctly describes the underlying orbifolded conifolds. The field theory can be obtained by a marginal deformation of the ${\cal N} = 1$ gauge theory on D3 branes at conifold singularity, the global symmetry being broken from $SU(2) \times SU(2)$ to $U(1) \times U(1)$. By using the AdS/CFT correspondence we argue that the marginal deformation is related to massless KK modes of NSNS and RR two form reduced on the compact space $T^{1,1}$. We build a $T^2$ fibration of $T^{1,1}$ and show that a D3 brane in the bulk correspond to a D5 brane on the $T^2$ fibre. We also discuss the possible brane construction of the system.

hep-th↗
arXiv1999

Closed Strings Interacting with Noncommutative D-branes

Closed string dynamics in the presence of noncommutative Dp-branes is investigated. In particular, we compute bulk closed string two-point scattering amplitudes; the bulk space-time geometries encoded in the amplitudes are shown to be consistent with the recently proposed background space-time geometries dual to noncommutative Yang-Mills theories. Three-point closed string absorption/emission amplitudes are obtained to show some features of noncommutative Dp-branes, such as modified pole structures and exponential phase factors linearly proportional to the external closed string momentum.

hep-th↗
arXiv1999

The Supercharges of Eleven-dimensional Supergraviton on Gravitational Wave Background

We find the explicit expression of the supercharges of eleven dimensional supergraviton on the background geometry of gravitational waves in asymptotically light-like compactified spacetime. We perform the calculations order by order in the fermions $\p$, while retaining all orders in bosonic degrees of freedom, and get the closed form up to $\p^5$ order. This should correspond to the supercharge of the effective action of (0+1)-dimensional matrix quantum mechanics for, at least, $v^4$ and $v^6$ order terms and their superpartners.

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arXiv1999

Non-perturbative membrane spin-orbit couplings in M/IIA theory

Membrane source-probe dynamics is investigated in the framework of the finite N-sector DLCQ M theory compactified on a transverse two-torus for an arbitrary size of the longitudinal dimension. The non-perturbative two fermion terms in the effective action of the matrix theory, the (2+1)-dimensional supersymmetric Yang-Mills theory, that are related to the four derivative F^4 terms by the supersymmetry transformation are obtained, including the one-loop term and full instanton corrections. On the supergravity side, we compute the classical probe action up to two fermion terms based on the classical supermembrane formulation in an arbitrary curved background geometry produced by source membranes satisfying the BPS condition; two fermion terms correspond to the spin-orbit couplings for membranes. We find precise agreement between two approaches when the background space-time is chosen to be that of the DLCQ M theory, which is asymptotically locally Anti-de Sitter.

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arXiv1999

Statistical Entropy and AdS/CFT Correspondence in BTZ Black Holes

We study AdS/CFT correspondence in the case of AdS3. We obtain the statistical entropy of the BTZ black hole in terms of the correct central charge and the conformal dimensions for the states corresponding to the BTZ black hole. We point out the difference between our method and the old fashioned approaches based on SL(2,R) Wess-Zumino-Witten model or Liouville theory.

hep-th↗
arXiv1999

Supersymmetric completion of supersymmetric quantum mechanics

Via supersymmetry argument, we determine the effective action of the SU(2) supersymmetric Yang-Mills quantum mechanics up to two constants, which results from the full supersymmetric completion of the F^4 term. The effective action, consisting of zero, two, four, six and eight fermion terms, agrees with the known perturbative one-loop calculations from the type II string theory and the matrix theory. Our derivation thus demonstrates its non-renormalization properties, namely, the one-loop exactness of the aforementioned action and the absence of the non-perturbative corrections. We briefly discuss generalizations to other branes and the comparison to the DLCQ supergravity analysis. In particular, our results show that the stringent constraints from the supersymmetry are responsible for the agreement between the matrix theory and supergravity with sixteen supercharges.

hep-th↗
arXiv1999

Eleven-dimensional massless superparticles and matrix theory spin-orbit couplings revisited

The classical probe dynamics of the eleven-dimensional massless superparticles in the background geometry produced by N source M-momenta is investigated in the framework of N-sector DLCQ supergravity. We expand the probe action up to the two fermion terms and find that the fermionic contributions are the spin-orbit couplings, which precisely agree with the matrix theory calculations. We comment on the lack of non-perturbative corrections in the one-loop matrix quantum mechanics effective action and its compatibility with the supergravity analysis.

hep-th↗
arXiv1998

Effective Action for Membrane Dynamics in DLCQ $M$ theory on a Two-torus

The effective action for the membrane dynamics on the background geometry of the $N$-sector DLCQ $M$ theory compactified on a two-torus is computed via supergravity. We compare it to the effective action obtained from the matrix theory, i.e., the (2+1)-dimensional supersymmetric Yang-Mills (SYM) theory, including the one-loop perturbative and full non-perturbative instanton effects. Consistent with the DLCQ prescription of $M$ theory {\em a la} Susskind, we find the precise agreement for the finite $N$-sector (off-conformal regime), as well as for the large $N$ limit (conformal regime), providing us with a concrete example of the correspondence between the matrix theory and the DLCQ $M$ theory. Non-perturbative instanton effects in the SYM theory conspire to yield the eleven-dimensionally covariant effective action.

hep-th↗
arXiv1998

Background geometry of DLCQ M theory on a p-torus and holography

Via supergravity, we argue that the infinite Lorentz boost along the M theory circle a la Seiberg toward the DLCQ M theory compactified on a p-torus (p<5) implies the holographic description of the microscopic theory. This argument lets us identify the background geometries of DLCQ $M$ theory on a p-torus; for p=0 (p=1), the background geometry turns out to be eleven-dimensional (ten-dimensional) flat Minkowski space-time, respectively. Holography for these cases results from the localization of the light-cone momentum. For p = 2,3,4, the background geometries are the tensor products of an Anti de Sitter space and a sphere, which, according to the AdS/CFT correspondence, have the holographic conformal field theory description. These holographic descriptions are compatible to the microscopic theory of Seiberg based on $\tilde{M}$ theory on a spatial circle with the rescaled Planck length, giving an understanding of the validity of the AdS/CFT correspondence.

hep-th↗
arXiv1997

Infinite Lorentz boost along the M-theory circle and non-asymptotically flat solutions in supergravities

Certain non-asymptotically flat but supersymmetric classical solution of the type IIA supergravity can be interpreted as the infinitely-boosted version of the D-particle solution along the M-theory circle. By a chain of T-dual transformations, this analysis also applies to yield non-asymptotically flat solutions from the asymptotically flat and (non)-extremal solutions with intersecting D-strings and D five-branes of the type IIB supergravity compactified on a five-torus. Under S-duality, the non-asymptotically flat solutions in this context can in particular be used to describe the (1+1)-dimensional CGHS type black holes via spontaneous compactifications.

hep-th↗
arXiv1997

Vortex solutions of a Maxwell-Chern-Simons field coupled to four-fermion theory

We find the static vortex solutions of the model of Maxwell-Chern-Simons gauge field coupled to a (2+1)-dimensional four-fermion theory. Especially, we introduce two matter currents coupled to the gauge field minimally: the electromagnetic current and a topological current associated with the electromagnetic current. Unlike other Chern-Simons solitons the N-soliton solution of this theory has binding energy and the stability of the solutions is maintained by the charge conservation laws.

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arXiv1995

N=2 Supersymmetric QCD and Four Manifolds; (I) the Donaldson and the Seiberg-Witten Invariants

We study the path integral of a twisted $N=2$ supersymmetric Yang-Mills theory coupled with hypermultiplet having the bare mass. We explicitly compute the topological correlation functions for the $SU(2)$ theory on a compact oriented simply connected simple type Riemann manifold with $b_2^+ \geq 3$. As the corollaries, we determine the topological correlation functions of the theory without the bare mass and those of the theory without coupling to the hypermultiplet. This includes a concrete field theoretic proof of the relation between the Donaldson and the Seiberg-Witten invariants.

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