Non chiral dynamical flavors and screening on the conifold
Francesco Bigazzi, Aldo L. Cotrone, Angel Paredes, Alfonso Ramallo
备注：
6 pages, 1 figure, previously unpublished results presented. Contribution to the proceedings of the RTN workshop "Constituents, Fundamental Forces and Symmetries of the Universe", Varna, Bulgaria, September 11-17, 2008
We present a new class of string theory solutions which are conjectured to be dual to the N=1 conifold theory by Klebanov and Witten coupled to non chiral massive dynamical flavors. These are introduced, in the Veneziano limit, by means of suitably embedded and smeared D7-branes whose full backreaction on the background is taken into account. The string solutions are used to study chromoelectric charge screening effects due to the dynamical flavors in the non perturbative regime of the dual gauge theories.
We explore the addition of fundamental matter to the Klebanov-Witten field theory. We add probe D7-branes to the ${\cal N}=1$ theory obtained from placing D3-branes at the tip of the conifold and compute the meson spectrum for the scalar mesons. In the UV limit of massless quarks we find the exact dimensions of the associated operators, which exhibit a simple scaling in the large-charge limit. For the case of massive quarks we compute the spectrum of scalar mesons numerically.
We present finite temperature solutions describing N_c D5 branes wrapped on the S^2 of the resolved conifold in the presence of N_f flavor brane sources and their backreaction, i.e. N_f/N_c ~ 1. In these solutions the dilaton does not blow up at infinity but stabilizes to a finite value. Thus, we can use them to generate new ones with D5 and D3 charge. The resulting backgrounds are non-extremal versions of the "flavored" resolved deformed conifold. It is tempting to interpret these solutions as gravity duals of finite temperature field theories exhibiting non-trivial phenomena as Seiberg duali…
It has been shown that non-Abelian solitonic vortex string supported in four-dimensional (4D) N = 2 supersymmetric QCD (SQCD) with the U(2) gauge group and $N_f = 4$ quark flavors becomes a critical superstring. This string propagates in the ten-dimensional space formed by a product of the flat 4D space and an internal space given by a Calabi-Yau noncompact threefold, namely, the conifold. The spectrum of low lying closed string states in the associated type IIA string theory was found and interpreted as a spectrum of hadrons in 4D N = 2 SQCD. In particular, the lowest string state appears to …
We consider a string dual of a partially topological $U(N)$ Chern-Simons-matter (PTCSM) theory recently introduced by Aganagic, Costello, McNamara and Vafa. In this theory, fundamental matter fields are coupled to the Chern-Simons theory in a way that depends only on a transverse holomorphic structure on a manifold; they are not fully dynamical, but the theory is also not fully topological. One description of this theory arises from topological strings on the deformed conifold $T^* S^3$ with $N$ Lagrangian 3-branes and additional coisotropic `flavor' 5-branes. Applying the idea of the Gopakuma…
We consider the addition of a large number of massive dynamical flavors to the Klebanov-Witten theory, the quiver gauge theory describing the low energy dynamics of Nc D3-branes at the conifold singularity. Massive flavors are introduced by means of Nf D7-branes which are holomorphically embedded and smeared along the transverse directions. After some general comments on the validity of the smearing procedure, we find the full backreacted supergravity solution corresponding to a particular class of massive embeddings. The solution depends on a running effective number of flavors, whose functio…
The conifold is a basic example of a noncompact Calabi-Yau threefold that admits a simple flop, and in M-theory, gives rise to a 5d hypermultiplet at low energies, realized by an M2-brane wrapped on the vanishing sphere. We develop a novel gauge-theoretic method to construct new classes of examples that generalize the simple flop to so-called length l=1,...,6. The method allows us to naturally read off the Gopakumar-Vafa invariants. Although they share similar properties to the beloved conifold, these threefolds are expected to admit M2-bound states of higher degree. We demonstrate this throug…
We consider D7-branes in the gauge theory/string theory correspondence, using a probe approximation. The D7-branes have four directions embedded holomorphically in a non-compact Calabi-Yau 3-fold (which for specificity we take to be the conifold) and their remaining four directions are parallel to a stack of D3-branes transverse to the Calabi-Yau space. The dual gauge theory, which has $\mathcal{N}=1$ supersymmetry, contains quarks which transform in the fundamental representation of the gauge group, and we identify the interactions of these quarks in terms of a superpotential. By activating t…
We discuss recent progress in describing a certain non-Abelian vortex string as a critical superstring on a conifold and clarify some subtle points. This particular solitonic vortex is supported in four-dimensional N=2 supersymmetric QCD with the U(2) gauge group, N_f=4 quark flavors and the Fayet-Iliopoulos term. Under certain conditions the non-Abelian vortex can become infinitely thin and can be interpreted as a critical ten-dimensional superstring. In addition to four translational moduli the non-Abelian vortex under consideration carries six orientational and size moduli. The vortex modul…
We derive novel solutions of flux compactification with D7-branes on the resolved conifold in type IIB String Theory and later extend this solution to allow for non-zero temperature. At zero temperature, we find that adding D7-branes via the Ouyang embedding contributes to the supersymmetry-breaking (1,2) imaginary-self-dual flux, without generating a bulk cosmological constant. We further find that having D7-branes and a resolved conifold together give rise to a non-trivial D-term on the D7-branes. This supersymmetry-breaking term vanishes when we take the singular conifold limit, although su…
As was shown recently, non-Abelian vortex strings supported in four-dimensional ${\cal N}=2$ supersymmetric QCD with the U(2) gauge group and $N_f=4$ quark multiplets (flavors) become critical superstrings. In addition to the translational moduli non-Abelian strings under consideration carry six orientational and size moduli. Together they form a ten-dimensional target space required for a superstring to be critical. The target space of the string sigma model is a product of the flat four-dimensional space and a Calabi-Yau non-compact threefold, namely, the conifold. We study closed string sta…
It has been shown that non-Abelian solitonic vortex strings supported in four-dimensional (4D) ${\mathcal N}=2\;$ supersymmetric QCD (SQCD) with the U($N=2$) gauge group and $N_f=4$ quark flavors behave as critical superstrings. In addition to four translational moduli non-Abelian strings under consideration carry six orientational and size moduli. Together they form a ten-dimensional space required for a superstring to be critical. The target space of the string sigma model is a product of the flat four-dimensional space $\mathbb{R}^4$ and a Calabi-Yau non-compact threefold $Y_6$, namely, the…
We study correlation functions of spatially separated static quark-antiquark pairs in (2+1)-flavor QCD in order to investigate onset and nature of color screening at high temperatures. We perform lattice calculations in a wide temperature range, $140 \le T \le 5814\,{\rm MeV}$, using the highly improved staggered quark action and several lattice spacings to control discretization effects. By comparing at high temperatures our lattice results to weak-coupling calculations as well as to the zero temperature result for the energy of a static quark-antiquark pair, we observe that color screening s…
In screening models with scalar-matter conformal coupling, we study the flavor transition of neutrinos. We employ an analytical method for studying the oscillation phase in a spherically symmetric spacetime filled by a scalar field. Since the ambient matter density determines the scalar field's behavior, an indirect environmental effect contributes to the flavor conversion inside matter. We evaluate the survival probabilities and show that the existence of the scalar field affects the oscillations of neutrinos. We discuss the results in the framework of screening mechanisms and the end, confro…
We present new supergravity backgrounds generated by N_c D5-branes, wrapping the S^2 of the resolved conifold, in the presence of N_f = 2 N_c smeared flavor D5-branes. The smearing allows us to take their backreaction on the geometry into account. We discuss the consistency, stability, and supersymmetry of these types of setups. We find near horizon geometries that we expect to be supergravity duals of SQCD-like theories with N_f= 2N_c. From these backgrounds we numerically extract rectangular Wilson loops and beta functions of the dual field theory for the regime where our approximations are …
We study non-Abelian vortex strings in four-dimensional (4D) $\mathcal{N} = 2$ supersymmetric QCD with U$(N=2)$ gauge group and $N_f=4$ flavors of quark hypermultiplets. It has been recently shown that these vortices behave as critical superstrings. The spectrum of closed string states in the associated string theory was found and interpreted as a spectrum of hadrons in 4D $\mathcal{N} = 2$ supersymmetric QCD. In particular, the lowest string state appears to be a massless BPS "baryon." Here we show the occurrence of this stringy baryon using a purely field-theoretic method. To this end we stu…
It has been shown that non-Abelian vortex string supported in four dimensional (4D) ${\mathcal N}=2$ supersymmetric QCD (SQCD) with the U(2) gauge group and $N_f = 4$ quark flavors becomes a critical superstring. This string propagates in the ten dimensional space formed by a product of the flat 4D space and an internal space given by a Calabi-Yau non-compact threefold, namely, the conifold. The spectrum of closed string states of the associated string theory was obtained using the equivalence between the critical string on the conifold and the non-critical string on the semi-infinite cigar de…
We analyze the question of screening versus confinement in bosonized massless QCD in two dimensions. We deduce the screening behavior of massless $SU(N_c)$ QCD with flavored fundamental fermions and fermions in the adjoint representation. This is done by computing the potential between external quarks as well as by bosonizing also the external sources and analyzing the states of the combined system. We write down novel "non-abelian Schwinger like" solutions of the equations of motion, compute their masses and argue that an exchange of massive modes of this type is associated with the screening…
The results for the Debye and Meissner screening masses of the gluons and the photon in the case of neutral and beta-equilibrated dense two-flavor quark matter are presented. In the limits of the normal phase and the ideal two-flavor color superconducting phase, the screening masses coincide with the known results. Most interestingly, we find that the Meissner screening masses squared can be negative, indicating a plasma-type chromomagnetic instability in dense quark matter.
We present a fully backreacted D3-D7 supergravity solution dual to the Klebanov-Strassler cascading gauge theory coupled to a large number of massive dynamical flavors in the Veneziano limit. The mass of the flavors can be larger or smaller than the dynamically generated scale. The solution is always regular at the origin of the radial coordinate and as such it can be suitably employed to explore the rich IR physics of the dual gauge theory. In this paper we focus on the static quark-antiquark potential, the screening of chromoelectric charges induced by the dynamical flavors, the flux tube br…
We investigate the confining properties of the QCD vacuum with $N_f=2$ flavors of dynamical quarks, and compare the results with the properties of the quenched theory. We use non-perturbatively $\mathcal{O}(a)$ improved Wilson fermions to keep cut-off effects small. We focus on color magnetic monopoles. Among the quantities we study are the monopole density and the monopole screening length, the static potential and the profile of the color electric flux tube. We furthermore derive the low-energy effective monopole action. Marked differences between the quenched and dynamical vacuum are found.
We examine the static potential in the presence of flavors in the perturbative backreacted D4/D8 system from localized D8 branes, focusing in particular on the Sakai-Sugimoto model. For the case of long strings we find the flavor corrections to the static potential which are of exponential form. We then investigate shorter Wilson loops and express their energy analytically in terms of the lengths of two neighboring Wilson loops. Moreover, we find that the static force for all the cases in the backreacted background is reduced compared to one in the probe limit, as expected due to screening eff…
Hadrons in $\mathcal{N}=2$ supersymmetric QCD from non-Abelian string on 2D black hole
William I. Fine Theoretical Physics Institute, University of Minnesota（明尼苏达大学威廉·I·费因理论物理研究所）；Skoltech（斯科尔科沃科学技术大学）；Dept. Math., HSE University（高等经济大学数学系）；NRC ‘‘Kurchatov Institute’’ - PNPI（库尔恰托夫国家研究中心——彼得堡核物理研究所）；HSE University（高等经济大学）
We use strongly coupled lattice QED with two flavors of massless staggered fermions to model the physics of pions in two-flavor massless QCD. Our model has the right chiral symmetries and can be studied efficiently with cluster algorithms. In particular we can tune the strength of the QCD anomaly and thus study its effects on the chiral phase transition. Our study confirms the widely accepted view point that the chiral phase transition is first order in the absence of the anomaly. Turning on the anomaly weakens the transition and turns it second order at a critical anomaly strength. The anomal…
In the context of [1]'s string theoretic dual of large-N thermal QCD-like theories at finite gauge/string coupling (as part of the `MQGP' limit of [2]), we discuss the following. First, up to LO in N, using the results of [3], we show that the local T^3 of [2] is the T^2-invariant sLag of [3] in a resolved conifold. This, together with the results of [4], shows that for a (predominantly resolved or deformed) resolved warped deformed conifold, the local T^3 of [2] in the MQGP limit, is the T^2-invariant sLag of [3] justifying the construction of the delocalized SYZ type IIA mirror of the type I…
We point out that chiral condensates at nonzero temperature and magnetic fields are in strict connection to the space-time integral of corresponding two-point neutral meson correlation functions in the pseudoscalar channel via the Ward-Takahashi identity. Screening masses of neutral pseudoscalar mesons, which are defined as the exponential decay of the corresponding spatial correlation functions in the long distance, thus are intrinsically connected to (inverse) magnetic catalysis of chiral condensates. To study this we performed lattice simulations of $(2+1)$-flavor QCD on $32^3\times N_t$ la…
We study the Peskin-Takeuchi S-parameter of holographic technicolor models. We present the recipe for computing the parameter in a generalized holographic setup. We then apply it to several holographic models that include: (a) the Sakai-Sugimoto model and (b) its non-compactified cousin, (c) a non-critical analog of (a) based on near extremal AdS_6 background, (d) the KMMW model which is similar to model (a) but with D6 and anti-D6 flavor branes replacing the D8 and anti-D8 branes, (e) a model based on D5 branes compactified on two S^1s with D7 and anti-7 probe branes and (f) the conifold mode…
Fermi gas of domain-wall Skyrmions in QCD in a strong magnetic field
International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM 2 ), Hiroshima University（可持续发展与扭结手性超物质国际研究所）；Hiroshima University（广岛大学）；Department of Physics, Yamagata University（山形大学物理系）；Yamagata University（山形大学）；Research and Education Center for Natural Sciences, Keio University（庆应义塾大学自然科学与教育中心）；Keio University（庆应义塾大学）；Department of Physics, Keio University（庆应义塾大学物理系）
We employ the string/gauge theory correspondence to study properties of strongly coupled quark-gluon plasmas in thermal gauge theories with a large number of colors and flavors. In particular, we analyze non-critical string duals of conformal (S)QCD, as well as ten dimensional wrapped fivebrane duals of SQCD-like theories. We study general properties of the dual plasmas, including the drag force exerted on a probe quark and the jet quenching parameter. We find that these plasma observables depend on the number of colors and flavors in the ``QCD dual''; in particular, we find that the jet quenc…
