519 research outputs found
On highest-energy state in the su(1|1) sector of N=4 super Yang-Mills theory
We consider the highest-energy state in the su(1|1) sector of N=4 super
Yang-Mills theory containing operators of the form tr(Z^{L-M} \psi^M) where Z
is a complex scalar and \psi is a component of gaugino. We show that this state
corresponds to the operator tr(\psi^L) and can be viewed as an analogue of the
antiferromagnetic state in the su(2) sector. We find perturbative expansions of
the energy of this state in both weak and strong 't Hooft coupling regimes
using asymptotic gauge theory Bethe ansatz equations. We also discuss a
possible analog of this state in the conjectured string Bethe ansatz equations.Comment: 23 pages, Late
Reduced sigma-model on AdS_5 x S^5: one-loop scattering amplitudes
We compute one-loop S-matrix in the reduced sigma-model which describes AdS_5
x S^5 string theory in the near-flat-space limit. The result agrees with the
corresponding limit of the S-matrix in the full sigma-model, which demonstrates
the consistency of the reduction at the quantum level.Comment: 9 pages, 1 figure; v2: reference added; v3: misprint in (3.6)
corrected; v4: typo in (3.4) corrected; v5: new form of the actio
Uniform Light-Cone Gauge for Strings in AdS_5 x S^5: Solving su(1|1) Sector
We introduce a uniform light-cone gauge for strings propagating in AdS
space-time. We use the gauge to analyze strings from the su(1|1) sector, and
show that the reduced model is described by a quadratic action for two complex
fermions. Thus, the uniform light-cone gauge allows us to solve the model
exactly. We analyze the near BMN spectrum of states from the su(1|1) sector and
show that it correctly reproduces the 1/J corrections. We also compute the
spectrum in the strong coupling limit, and derive the famous \lambda^{1/4}
asymptotics. We then show that the same string spectrum can be also derived by
solving Bethe ansatz type equations, and discuss their relation to the quantum
string Bethe ansatz for the su(1|1) sector.Comment: 26 pages, Latex, v2: comparison to the strong coupling expansion of
the quantum string Bethe ansatz is added, discussion of the winding sector is
extended, references adde
Bethe Ansatz solutions for highest states in SYM and AdS/CFT duality
We consider the operators with highest anomalous dimension in the
compact rank-one sectors and of super Yang-Mills. We study the flow of from weak to strong 't
Hooft coupling by solving (i) the all-loop gauge Bethe Ansatz, (ii)
the quantum string Bethe Ansatz. The two calculations are carefully compared in
the strong coupling limit and exhibit different exponents in the leading
order expansion . We find and
for the gauge or string solution. This strong coupling discrepancy is not
unexpected, and it provides an explicit example where the gauge Bethe Ansatz
solution cannot be trusted at large . Instead, the string solution
perfectly reproduces the Gubser-Klebanov-Polyakov law . In particular, we provide an analytic expression for the
integer level as a function of the U(1) charge in both sectors.Comment: 42 pages, JHEP style LaTe
Integrable Spin Chains on the Conformal Moose
We consider N=1, D=4 superconformal U(N)^{pq} Yang-Mills theories dual to
AdS_5xS^5/Z_pxZ_q orbifolds. We construct the dilatation operator of this
superconformal gauge theory at one-loop planar level. We demonstrate that a
specific sector of this dilatation operator can be thought of as the transfer
matrix for a two-dimensional statistical mechanical system, related to an
integrable SU(3) anti-ferromagnetic spin chain system, which in turn is
equivalent to a 2+1-dimensional string theory where the spatial slices are
discretized on a triangular lattice. This is an extension of the SO(6) spin
chain picture of N=4 super Yang-Mills theory. We comment on the integrability
of this N=1 gauge theory and hence the corresponding three-dimensional
statistical mechanical system, its connection to three-dimensional lattice
gauge theories, extensions to six-dimensional string theories, AdS/CFT type
dualities and finally their construction via orbifolds and brane-box models. In
the process we discover a new class of almost-BPS BMN type operators with large
engineering dimensions but controllably small anomalous corrections.Comment: 53 pages, 14 eps figures; Added reference
Two-loop world-sheet corrections in AdS_5 x S^5 superstring
We initiate the computation of the 2-loop quantum AdS_5 x S^5 string
corrections on the example of a certain string configuration in S^5 related by
an analytic continuation to a folded rotating string in AdS_5 in the ``long
string'' limit. The 2-loop term in the energy of the latter should represent
the subleading strong-coupling correction to the cusp anomalous dimension and
thus provide a further check of recent conjectures about the exact structure of
the Bethe ansatz underlying the AdS/CFT duality. We use the conformal gauge and
several choices of the \kappa-symmetry gauge. While we are unable to verify the
cancellation of 2d UV divergences we compute the bosonic contribution to the
effective action and also determine the non-trivial finite part of the
fermionic contribution. Both the bosonic and the fermionic contributions to the
string energy happen to be proportional to the Catalan's constant. The
resulting value for 2-loop superstring prediction for the subleading
coefficient a_2 in the scaling function matches the numerical value found in
hep-th/0611135 from the BES equation.Comment: 48 pages, 1 Figure. v3: several mistakes corrected, the finite result
for the 2-loop coefficient is found to agree with the numerical value found
by Benna et al in hep-th/061113
Quark Coulomb Interactions and the Mass Difference of Mirror Nuclei
We study the Okamoto-Nolen-Schiffer (ONS) anomaly in the binding energy of
mirror nuclei at high density by adding a single neutron or proton to a quark
gluon plasma. In this high-density limit we find an anomaly equal to two-thirds
of the Coulomb exchange energy of a proton. This effect is dominated by quark
electromagnetic interactions---rather than by the up-down quark mass
difference. At normal density we calculate the Coulomb energy of neutron matter
using a string-flip quark model. We find a nonzero Coulomb energy because of
the neutron's charged constituents. This effect could make a significant
contribution to the ONS anomaly.Comment: 4 pages, 2 figs. sub. to Phys. Rev. Let
Infinite spin limit of semiclassical string states
Motivated by recent works of Hofman and Maldacena and Dorey we consider a
special infinite spin limit of semiclassical spinning string states in AdS5 x
S5. We discuss examples of known folded and circular 2-spin string solutions
and demonstrate explicitly that the 1-loop superstring correction to the
classical expression for the energy vanishes in the limit when one of the spins
is much larger that the other. We also give a general discussion of this limit
at the level of integral equations describing finite gap solutions of the
string sigma model and argue that the corresponding asymptotic form of the
string and gauge Bethe equations is the same.Comment: 38 pages, 3 figures; v2: comments on derivation of bound states of
magnons from discrete Bethe equations added in section 4 and appendix C,
references added, Imperial-TP-AT-6-4, HUTP-06/A002
Acute effects of cannabinoids on addiction endophenotypes are moderated by genes encoding the CB1 receptor and FAAH enzyme
Understanding genetic factors that contribute to cannabis use disorder (CUD) is important, but to date, findings have been equivocal. Singleânucleotide polymorphisms (SNPs) in the cannabinoid receptor 1 gene (CNR1; rs1049353 and rs806378) and fatty acid amide hydrolase (FAAH) gene (rs324420) have been implicated in CUD. Their relationship to addiction endophenotypes such as cannabisârelated state satiety, the salience of appetitive cues, and craving after acute cannabinoid administration has not been investigated. Fortyâeight cannabis users participated in a doubleâblind, placeboâcontrolled, fourâway crossover experiment where they were administered treatments in a randomized order via vaporization: placebo, Î9âtetrahydrocannabinol (THC) (8 mg), THC + cannabidiol (THC + CBD) (8 + 16 mg), and CBD (16 mg). Cannabisârelated state satiety, appetitive cue salience (cannabis and food), and cannabis craving were assessed each day. Participants were genotyped for rs1049353, rs806378, and rs324420. Results indicated that CNR1 rs1049353 GG carriers showed increased state satiety after THC/THC + CBD administration in comparison with placebo and reduced the salience of appetitive cues after THC in comparison with CBD administration; A carriers did not vary on either of these measures indicative of a vulnerability to CUD. CNR1 rs806378 CC carriers showed greater salience to appetitive cues in comparison with T carriers, but there was no evidence for changes in state satiety. FAAH rs324420 A carriers showed greater bias to appetitive cues after THC, in comparison with CC carriers. FAAH CC carriers showed reduced bias after THC in comparison with CBD. No SNPs modulated craving. These findings identify candidate neurocognitive mechanisms through which endocannabinoid system genetics may influence vulnerability to CUD
1/J corrections to semiclassical AdS/CFT states from quantum Landau-Lifshitz model
One way to relate semiclassical string states and dual gauge theory states is
to show the equivalence between their low-energy effective 2d actions. The
gauge theory effective action, which is represented by an effective
Landau-Lifshitz (LL) model, was previously found to match with the string
theory world-sheet action up to the first two orders in the effective parameter
, where is the `t Hooft coupling
and is the total -charge. Here we address the question if quantizing the
effective LL action reproduces the subleading 1/J corrections to the spin chain
energies as well as the quantum corrections to the string energies. We
demonstrate that this is indeed the case provided one chooses an appropriate
regularization of the effective LL theory. Expanding near the BPS vacuum, we
show that the quantum LL action gives the same 1/J corrections to energies of
BMN states as found previously on the gauge theory and string theory sides. We
also compute the subleading corrections and show that these too match
with corrections computed from the Bethe ansatz. We also compare the results
from the LL action with a more direct computation from the spin chain. We
repeat the same computation for the -deformed LL action and find that
the quantum LL result is again equal to the 1/J correction computed from the
-deformed Bethe ansatz equations. We also quantize the LL action near
the rotating circular and folded string solutions, generalizing the known
gauge/string results for 1/J corrections to the classical energies. We
emphasize the simplicity of this effective field theory approach as compared to
the full quantum string computations.Comment: 52 pages, references adde
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