36 research outputs found
Elaborations on the String Dual to N=1 SQCD
In this paper we make further refinements to the duality proposed between N=1
SQCD and certain string (supergravity plus branes) backgrounds, working in the
regime of comparable large number of colors and flavors. Using the string
theory solutions, we predict different field theory observables and phenomena
like Seiberg duality, gauge coupling and its running, the behavior of Wilson
and 't Hooft loops, anomalous dimensions of the quark superfields, quartic
superpotential coupling and its running, continuous and discrete anomaly
matching. We also give evidence for the smooth interpolation between higgsed
and confining vacua. We provide several matchings between field theory and
string theory computations.Comment: 44 pages, 6 figures. References added, minor rewritings, published
versio
Chiral symmetry breaking as open string tachyon condensation
We consider a general framework to study holographically the dynamics of
fundamental quarks in a confining gauge theory. Flavors are introduced by
placing a set of (coincident) branes and antibranes on a background dual to a
confining color theory. The spectrum contains an open string tachyon and its
condensation describes the U(N_f)_L x U(N_f)_R -> U(N_f)_V symmetry breaking.
By studying worldvolume gauge transformations of the flavor brane action, we
obtain the QCD global anomalies and an IR condition that allows to fix the
quark condensate in terms of the quark mass. We find the expected N_f^2
Goldstone bosons (for m_q=0), the Gell-Mann-Oakes-Renner relation (for m_q
small) and the \eta' mass. Remarkably, the linear confinement behavior for the
masses of highly excited spin-1 mesons, m_n^2 ~ n is naturally reproduced.Comment: 30 pages + 5 appendices, 2 figure
Non-critical holography and four-dimensional CFT's with fundamentals
We find non-critical string backgrounds in five and eight dimensions,
holographically related to four-dimensional conformal field theories with N=0
and N=1 supersymmetries. In the five-dimensional case we find an AdS_5
background metric for a string model related to non-supersymmetric, conformal
QCD with large number of colors and flavors and discuss the conjectured
existence of a conformal window from the point of view of our solution. In the
eight-dimensional string theory, we build a family of solutions of the form
AdS_5 x \tilde{S}^3 with \tilde{S}^3 a squashed three-sphere. For a special
value of the ratio N_f/N_c, the background can be interpreted as the
supersymmetric near-horizon limit of a system of color and flavor branes on
R^{1,3} times a known four-dimensional generalization of the cigar. The N=1
dual theory with fundamental matter should have an IR fixed point only for a
fixed ratio N_f/N_c. General features of the string/gauge theory correspondence
for theories with fundamental flavors are also addressed.Comment: 38 pages, 3 figures; JHEP class. Minor corrections, references adde
Phases and geometry of the N=1 A_2 quiver gauge theory and matrix models
We study the phases and geometry of the N=1 A_2 quiver gauge theory using
matrix models and a generalized Konishi anomaly. We consider the theory both in
the Coulomb and Higgs phases. Solving the anomaly equations, we find that a
meromorphic one-form sigma(z)dz is naturally defined on the curve Sigma
associated to the theory. Using the Dijkgraaf-Vafa conjecture, we evaluate the
effective low-energy superpotential and demonstrate that its equations of
motion can be translated into a geometric property of Sigma: sigma(z)dz has
integer periods around all compact cycles. This ensures that there exists on
Sigma a meromorphic function whose logarithm sigma(z)dz is the differential. We
argue that the surface determined by this function is the N=2 Seiberg-Witten
curve of the theory.Comment: 41 pages, 2 figures, JHEP style. v2: references adde
Quivers via anomaly chains
We study quivers in the context of matrix models. We introduce chains of
generalized Konishi anomalies to write the quadratic and cubic equations that
constrain the resolvents of general affine and non-affine quiver gauge
theories, and give a procedure to calculate all higher-order relations. For
these theories we also evaluate, as functions of the resolvents, VEV's of
chiral operators with two and four bifundamental insertions. As an example of
the general procedure we explicitly consider the two simplest quivers A2 and
A1(affine), obtaining in the first case a cubic algebraic curve, and for the
affine theory the same equation as that of U(N) theories with adjoint matter,
successfully reproducing the RG cascade result.Comment: 32 pages, latex; typos corrected, published versio
Penrose limit of a non-supersymmetric RG fixed point
We extend the BMN duality between IIB superstring theory on a pp-wave
background and a sector of N=4 super Yang-Mills theory to the
non-supersymmetric and unstable background built by Romans as a
compactification on a U(1) bundle over CP2 with 3-form and 5-form field
strength fluxes. We obtain a stable theory with the fewest number of
supercharges (e.g. 16) allowed by this kind of solutions and make conjectures
on the dual gauge theory.Comment: 30 pages, latex; v2 typos corrected; v3 typos corrected, Nuclear
Physics B versio
Fundamental matter, meson spectroscopy and non-critical string/gauge duality
We discuss the incorporation of quarks in the fundamental representation of
the color group into the non-critical string/gauge duality. We focus on
confining theories and address this question using two different approaches:
(i) by introducing flavor probe branes and (ii) by deriving backreacted
flavored near extremal gravity backgrounds. In the former approach we analyze
the near extremal AdS_6 model with D4 and anti-D4 probe flavor branes included.
We study the meson spectrum and discuss the role played by the constituent
quark mass, related to the integration constant that defines the embedding. As
for the second approach we derive a class of flavored AdS_{n+1} x S^k black
hole solutions. In particular we write down the flavored AdS_6 and AdS_5 black
holes and the near extremal AdS_5 x S^1 backgrounds. We analyze several gauge
dynamical properties associated with these models.Comment: 46 pages, 7 figures. v.2: some references and a comment about the
comparison with analogous critical models were added. v.3: a comment added;
published versio
Spermine oxidase (SMO) activity in breast tumor tissues and biochemical analysis of the anticancer spermine analogues BENSpm and CPENSpm
Background: Polyamine metabolism has a critical role in cell death and proliferation representing a potential
target for intervention in breast cancer (BC). This study investigates the expression of spermine oxidase (SMO) and
its prognostic significance in BC. Biochemical analysis of Spm analogues BENSpm and CPENSpm, utilized in
anticancer therapy, was also carried out to test their property in silico and in vitro on the recombinant SMO
enzyme.
Methods: BC tissue samples were analyzed for SMO transcript level and SMO activity. Studentâs t test was applied
to evaluate the significance of the differences in value observed in T and NT samples. The structure modeling
analysis of BENSpm and CPENSpm complexes formed with the SMO enzyme and their inhibitory activity, assayed
by in vitro experiments, were examined.
Results: Both the expression level of SMO mRNA and SMO enzyme activity were significantly lower in BC samples
compared to NT samples. The modeling of BENSpm and CPENSpm complexes formed with SMO and their
inhibition properties showed that both were good inhibitors.
Conclusions: This study shows that underexpression of SMO is a negative marker in BC. The SMO induction is a
remarkable chemotherapeutical target. The BENSpm and CPENSpm are efficient SMO inhibitors. The inhibition
properties shown by these analogues could explain their poor positive outcomes in Phases I and II of clinical trials