148,371 research outputs found
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ผ๋ฌธ (๋ฐ์ฌ)-- ์์ธ๋ํ๊ต ๋ํ์ : ๋ฌผ๋ฆฌยท์ฒ๋ฌธํ๋ถ ๋ฌผ๋ฆฌํ์ ๊ณต, 2015. 8. ๊น์.This thesis aims at studying the higher dimensional quantum field theories, engi- neered from the string theory. These theories are genuinely strongly interactive, thus being difficult to be understood within the conventional QFT framework. In particular, I focus on those 5d / 6d QFTs which can be deformed to the weakly coupled 5d Yang-Mills theories, in which the deformation is caused either by a rel- evant operator or by a circle compactification. Instantons are crucial for observing the physics of 5d / 6d QFTs which correspond to the UV fixed points of certain 5d SYMs. In the first half of the thesis, I obtain the general expression for the instanton partition function of 5d SYMs and apply it to study the spectrum of various UV QFTs. The second half focuses on the 6d non-critical strings, which are key objects of 6d QFTs. Two types of 6d strings, M-strings and E-strings, are considered, for which the worldsheet gauge theories are explicitly developed.Abstract .......................... i
1 Introduction .......................... 1
2 Higher-dimensional QFTs .......................... 9
2.1 Six-dimensional theory .......................... 9
2.1.1 6d (2,0) theory .......................... 9
2.1.2 6d (1,0) theory .......................... 11
2.2 Five-dimensional theory ......................... 15
3 Instanton calculus in 5d gauge theory .......................... 19
3.1 Yang-Mills instantons .......................... 20
3.2 Instanton counting and Seiberg-Witten solution ........... 26
3.3 ADHM quantum mechanics ....................... 29
3.4 Exact computation of the 1d index................... 33
3.4.1 Rank-1 gauge group ....................... 36
3.4.2 Higher-rank gauge group .................... 42
3.5 Examples ................................. 49
3.5.1 N=1? theories.......................... 49
3.5.2 U(N) theories with matters and Chern-Simons term ...... 61
3.5.3 Sp(N)theories .......................... 64
4 Application of instanton calculus .......................... 69
4.1 6d (2,0) SCFT .............................. 69
4.2 U(N) theories for 5d SCFTs....................... 71
4.3 5d SCFT from D4-D8-O8 configuration ................ 74
4.3.1 Direct computations of the D0-D8-O8 indices ................. 80
4.3.2 Superconformal indices ..................... 81
4.4 6d (1,0) SCFT with E8 flavor symmetry................ 89
5 Non-critical strings in 6d QFTs ................. 95
5.1 M-strings in 6d (2,0) SCFT....................... 96
5.2 E-strings in 6d (1,0) E8 SCFT ..................... 99
5.2.1 The brane setup and the 2d (0,4) gauge theories ....... 100
5.2.2 E-string elliptic genera from 2d gauge theories ........ 111
5.2.3 Comparison with the instanton partition function ....... 135
A Characters of SO(2Nf) 141
B Modular forms and Jacobi forms 142
C Details of computation 147
C.1 Genus expansions of topological string amplitudes ................. 147
C.2 Exact properties of the E-string elliptic genus ................. 149
Bibliography ................. 163Docto
Photochemical Pump and NMR Probe to monitor the formation and kinetics of hyperpolarized metal dihydrides
On reaction of IrI(CO)(PPh 3) 21with para-hydrogen(p-H 2),Ir(H) 2I(CO)(PPh 3) 22 is formed which exhibits strongly enhanced 1H NMR signals for its hydride resonances. Complex 2 also shows similar enhancement of its NMR spectra when it is irradiated under p-H 2. We report the use of this photochemical reactivity to measure the kinetics of H 2 addition by laser-synchronized reactions in conjunction with NMR. The single laser pulse promotes the reductive elimination of H 2 from Ir(H) 2I(CO)(PPh 3) 22 in C 6D 6 solution to form the 16-electron precursor 1, back reaction with p-H 2 then reforms 2 in a well-defined nuclear spin-state. The build up of this product can be followed by incrementing a precisely controlled delay (ฯ), in millisecond steps, between the laser and the NMR pulse. The resulting signal vs. time profile shows a dependence on p-H 2 pressure. The plot of k obs against p-H 2 pressure is linear and yields the second order rate constant, k 2, for H 2 addition to 1 of (3.26 ยฑ 0.42) ร 10 2 M โ1 s โ1. Validation was achieved by transient-UV-vis absorption spectroscopy which gives k 2 of (3.06 ยฑ 0.40) ร 10 2 M โ1 s โ1. Furthermore, irradiation of a C 6D 6 solution of 2 with multiple laser shots, in conjunction with p-H 2 derived hyperpolarization, allows the detection and characterisation of two minor reaction products, 2a and 3, which are produced in such low yields that they are not detected without hyperpolarization. Complex 2a is a configurational isomer of 2, while 3 is formed by substitution of CO by PPh
Entropy of Pairs of Dual Attractors in 6D/7D
We study the attractor mechanism of dual pairs of black brane bounds in N=2
supergravity in six and seven dimensions. First, we consider the effective
potentials of the 6D and 7D black branes as well as their entropies. The
contribution coming from the SO(1,1) factor of the moduli spaces M_{6D} and
M_{7D} of these theories is carefully analyzed and it is used to motivate the
study of the dual black branes bounds; which in turn allow to fix the critical
value of the dilaton at horizon. The attractor eqs of the black branes and the
bound pairs are derived by combining the criticality conditions of the
corresponding effective potentials and the Lagrange multiplier method capturing
constraints eqs on the fields moduli.Comment: 55 pages, 2 figures, To appear in JHE
Warped compactification on curved manifolds
The characterization of a six- (or seven)-dimensional internal manifold with
metric as having positive, zero or negative curvature is expected to be an
important aspect of warped compactifications in supergravity. In this context,
Douglas and Kallosh recently pointed out that a compact internal space with
negative curvature could help to construct four-dimensional de Sitter solutions
only if the extra dimensions are strongly warped or there are large stringy
corrections. That is, the problem of finding 4-dimensional de Sitter solutions
is well posed, if all extra dimensions are physically compact, which is called
a no-go theorem. Here, we show that the above conclusion does not extend to a
general class of warped compactifications in classical supergravity that allow
a non-compact direction or cosmological solutions for which the internal space
is asymptotic to a cone over a product of compact Einstein spaces or spheres.
For clarity, we present classical solutions that compactify higher-dimensional
spacetime to produce a Robertson--Walker universe with de Sitter-type expansion
plus one extra non-compact direction. Such models are found to admit both an
effective four-dimensional Newton constant that remains finite and a
normalizable zero-mode graviton wavefunction. We also exhibit the possibility
of obtaining 4D de Sitter solutions by including the effect of fluxes (p-form
field strengths).Comment: 24 pages, 1 figure; v5 significant changes in the presentation,
published (journal) versio
Gravitational Forces on a Codimension-2 Brane
We compute the gravitational response of six dimensional gauged, chiral
supergravity to localized stress energy on one of two space-filling branes,
including the effects of compactifying the extra dimensions and brane
back-reaction. We find a broad class of exact solutions, including various
black-brane solutions. Several approximate solutions are also described, such
as the near-horizon geometry of a small black hole which is argued to be
approximately described by a 6D Schwarzschild (or Kerr) black hole, with event
horizon appropriately modified to encode the brane back-reaction. The general
linearized far-field solutions are found in the 4D regime very far from the
source, and all integration constants are related to physical quantities
describing the branes and the localized energy source. The localized source
determines two of these, corresponding to the source mass and the size of the
strength of a coupling to a 4D scalar mode whose mass is parametrically smaller
than the KK scale. At large distances the solutions agree with those of 4D
general relativity, but for an intermediate range of distances (larger than the
KK scale) the solutions better fit a Brans-Dicke theory. For a realistic choice
of parameters the KK scale could lie at a micron, while the crossover to
Brans-Dicke behaviour could occur at around 10 microns. While allowed by
present data this points to potentially measurable changes to Newton's Law
arising at distances larger than the KK scale.Comment: 31 pages + appendices, 2 figure
Towards the Classification of Non-Marginal Bound States of M-branes and Their Construction Rules
We present a systematic analysis of possible bound states of M-brane
solutions (including waves and monopoles) by using the solution generating
technique of reduction of M-brane to 10 dimensions, use of T-duality and then
lifting back to 11 dimensions. We summarize a list of bound states for one- and
two-charge cases including tilted brane solutions. Construction rules for these
non-marginal solutions are also discussed.Comment: Latex, 37 page
Six-dimensional localized black holes: numerical solutions
To test the strong-gravity regime in Randall-Sundrum braneworlds, we consider
black holes bound to a brane. In a previous paper, we studied numerical
solutions of localized black holes whose horizon radii are smaller than the AdS
curvature radius. In this paper, we improve the numerical method and discuss
properties of the six dimensional (6D) localized black holes whose horizon
radii are larger than the AdS curvature radius. At a horizon temperature
, the thermodynamics of the localized black
hole undergo a transition with its character changing from a 6D Schwarzschild
black hole type to a 6D black string type. The specific heat of the localized
black holes is negative, and the entropy is greater than or nearly equal to
that of the 6D black strings with the same thermodynamic mass. The large
localized black holes show flattened horizon geometries, and the intrinsic
curvature of the horizon four-geometry becomes negative near the brane. Our
results indicate that the recovery mechanism of lower-dimensional Einstein
gravity on the brane works even in the presence of the black holes.Comment: 17 pages, 9 figures, RevTeX4, typos correcte
Nearing Extremal Intersecting Giants and New Decoupled Sectors in N = 4 SYM
We study near-horizon limits of near-extremal charged black hole solutions to
five-dimensional gauged supergravity carrying two charges, extending
the recent work of Balasubramanian et.al. We show that there are two
near-horizon decoupling limits for the near-extremal black holes, one
corresponding to the near-BPS case and the other for the far from BPS case.
Both of these limits are only defined on the 10d IIB uplift of the 5d black
holes, resulting in a decoupled geometry with a six-dimensional part (conformal
to) a rotating BTZ X . We study various aspects of these decoupling limits
both from the gravity side and the dual field theory side. For the latter we
argue that there should be two different, but equivalent, dual gauge theory
descriptions, one in terms of the 2d CFT's dual to the rotating BTZ and the
other as certain large R-charge sectors of d=4,N =4 U(N) SYM theory. We discuss
new BMN-type sectors of the N=4 SYM in the limit in which the
engineering dimensions scale as (for the near-BPS case) and as
(for the far from BPS case).Comment: 44 pages, references added, minor change
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