arXiv subjects

Aalok Misra

Publications and source records attributed to Aalok Misra.

At least 37 records · Page 2Linked to original sources

arXiv2015

Transport Coefficients of Black MQGP M3-Branes

The SYZ mirror, in the `delocalized limit' of [1], of (M)N (fractional)D3-branes, and wrapped N_f flavor D7-branes in the presence of a black-hole resulting in a non-Kaehler resolved warped deformed conifold (NKRWDC) in [2], was carried out in [3] and resulted in black M3-branes. The uplift, if valid globally(like [4] for fractional D3 branes in conifolds), asymptotes to M5-branes wrapping a two-cycle (homologously an (large) integer sum of two-spheres) in AdS_5xM_6. Interestingly, in the MQGP limit, assuming the deformation > resolution, by estimating the five SU(3) structure torsion (τ) classes W_{1,2,3,4,5} we show that τ\in W_4+W_5: 2/3 Re(W^3bar_5)=W^3bar_4 in the UV, implying the NKRWDC locally preserves SUSY. Further, the local T^3 of [3] in the large-r limit and the `MQGP' limit of [3], satisfies the same conditions as the maximal T^2-invariant special Lagrangian three-cycle of T^*(S^3) of [6], partly justifying use of local SYZ mirror symmetry in [3]. Using the Ouyang embedding in the DBI action of a D7-brane or by dimensionally reducing the 11-dimensional EH action to five (R^{1,3},r) dimensions, we then calculate a variety of gauge and metric-perturbation-modes' two-point functions using the prescription of [5], and show: (i) diffusion constant D~1/T, (ii) the electrical conductivity σ~T, (iii) the charge susceptibility χ~ T^2, (iv) [using (i) - (iii)] the Einstein's relation σ/χ=D, is indeed satisfied, (v) the R-charge diffusion constant D_R~1/T, and (vi) the possibility of generating η/s=1/4pi from solutions to the vector and tensor mode metric perturbations' EOMs, separately. All results are also valid in the limit of [2].

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arXiv2015

Towards MQGP

For the Ouyang embedding we calculate the chemical potential mu_C due to a U(1) gauge field on the w.v. of N_f D7-branes wrapped around a 4-cycle in a resolved warped deformed conifold with (M)N (fractional)D3-branes of [1], and show the possible thermodynamical stability up to linear order in the embedding parameter. In the spirit of [2] we obtain the local type IIA mirror using SYZ mirror symmetry near (theta_{1,2},psi)=( ,{0,2pi,,4pi}) and then oxidize the same to M theory. We take two limits of this uplift:(i)g_s,g_sN_f,g_sM^2/N,g_s^2M N_f<<1,g_sM,g_sN>>1 similar to [1] effected by M eps^{-3d/2}, N eps^{-19d},g_s epsn^d,d>0 and eps<=O(0.01);(ii)the `MQGP limit' g_sM^2/N<<1, g_sN>>1 for finite g_s,M, effected by: g_s eps, M eps^{-3d/2},N eps^{-39d},d>0, eps<~1). The second limit is more suited for the study of QGP (See [3]) and can only be addressed in M theory. The uplift gives a black M3-brane solution whose near-horizon geometry near theta_{1,2}=0,pi-branches, preserves 1/8 SUSY. We obtain eta/s=1/4pi for the uplift and the diffusion constant for types IIB/IIA backgrounds comes out to be ~1/T, for both limits. The D=11 SUGRA action up to O(R^4,|G_4|^2) is expected to receive dominant contributions near =0,pi due to poles. Introducing a small-angle cut-off c and using the =c,(pi-c)-local uplift the specific heat from the IR-finite part of the action (c-independent) turns out to be positive indicative of the thermodynamical stability of the uplift. An ALD-gravity-type interpretation can be given to the counter-terms for(i). Its verified that the black M3-brane entropy S r_h^3 from M-theoretic thermodynamical methods and the horizon areas of types IIB/IIA/M3-brane solutions.

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arXiv2014

A Healthy Electron/Neutron EDM in D3/D7 mu-Split-Like SUSY

Within the framework of N=1 gauged supergravity, using a phenomenological model which can be obtained locally as a Swiss-Cheese Calabi-Yau string-theoretic compactification with a mobile D3-brane localized on a nearly sLag three-cycle in the Calabi-Yau and fluxed stacks of wrapped D7-branes, and which provides a natural realization of mu-Split SUSY, we show that in addition to getting a significant value of electron/neutron EDM d_{e,n}/e at two-loop level, one can obtain a sizable contribution of d_{e,n}/e even at one-loop level. We obtain d_{e}/e ~ O(10^{-29}) cm from two-loop diagrams involving heavy sfermions and a light Higgs, and d_{e}/e ~ O(10^{-32}) cm from one-loop diagram involving heavy chargino and a light Higgs. Also, d_{n}/e ~ O(10^{-33}) cm from one-loop diagram involving SM-like quarks and Higgs. Next, by considering a Barr-Zee diagram involving W bosons and Higgs, and conjecturing that the CP-violating phase can appear from a linear combination of Higgs doublet obtained in the context of mu-split SUSY, we obtain d_{e,n}/e ~ O(10^{-27}) cm at two-loop level .

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arXiv2013

(N)LSP Decays and Gravitino Dark Matter Relic Abundance in Big Divisor (nearly) SLagy D3/D7 mu-Split SUSY

Using the (nearly) Ricci-flat Swiss-Cheese metric of [1], in the context of a mobile space-time filling D3-brane restricted to a nearly special Lagrangian sub-manifold (in the large volume limit, the pull-back of the Kaehler form close to zero and the real part of the pull-back of e^{-i theta},theta=pi/2 times the nowhere-vanishing holomorphic three-form providing the volume form on the three-cycle) of the "big" divisor with (fluxed stacks of) space-time filling D7-branes also wrapping the "big" divisor (corresponding to a local minimum), we provide an explicit identification of the electron and the u-quark, as well as their SU(2)_L-singlet cousins, with fermionic super-partners of four Wilson line moduli; their superpartners turn out to be very heavy, the Higgsino-mass parameter turns out to be large, one obtains one light (with a mass of 125 GeV) and one heavy Higgs and the gluino is long lived (from a collider point of view) providing a possible realization of "mu-Split Supersymmetry". By explicitly calculating the lifetimes of decays of the co-NLSPs - the first generation squark/slepton and a neutralino - to the LSP - the gravitino - as well as gravitino decays, we verify that BBN constraints relevant to the former as well as the requirement of the latter to be (more than) the age of the universe, are satisfied. For the purpose of calculation of the gravitino relic abundance in terms of the neutralino/slepton relic abundance, we evaluate the latter by evaluating the netralino/slepton (co-)annihilation cross sections and hence show that the former satisfies the requirement for a Dark Matter candidate.

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arXiv2012

Local D3/D7 mu-Split SUSY, 125 GeV Higgs and Large Volume Ricci-Flat Swiss-Cheese Metrics: A Brief Review

In this article, we review briefly recent progress made in realizing local(ized around a mobile space-time filling D3-brane in) D3/D7 mu-Split Supersymmetry in (the large volume limit of Type IIB) String Theory (compactified on Swiss-Cheese Calabi-Yau orientifolds) as well as obtaining a 125 GeV (light) Higgs in the same set up. We also discuss obtaining the geometric Kaehler potential (and hence the Ricci-Flat metric) for the Swiss-Cheese Calabi-Yau in the large volume limit using the Donaldson's algorithm and intuition from GLSM-based calculations - we present new results for Swiss-Cheese Calabi-Yau (used in the set up) metrics at points finitely away from the "big" divisor.

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arXiv2012

Towards Large Volume Big Divisor D3-D7 "mu-Split Supersymmetry" and Ricci-Flat Swiss-Cheese Metrics, and Dimension-Six Neutrino Mass Operators

We show that it is possible to realize a "mu-split SUSY" scenario [1] in the context of large volume limit of type IIB compactifications on Swiss-Cheese Calabi-Yau's in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the "big" divisor Sigma_B. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy Higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of mu-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the 3-body decays of the gluino into a quark, a squark and a neutralino or Goldstino, as well as 2-body decays of the gluino into either a neutralino or a Goldstino and a gluon. Guided by the geometric Kaehler potential for Sigma_B obtained in [2] based on GLSM techniques, and the Donaldson's algorithm [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in [4] pertaining to our proposed metric for the full Swiss-Cheese Calabi-Yau, but for simplicity of calculation, close to Sigma_B, which is Ricci-flat in the large volume limit. Also, as an application of the one-loop RG flow solution for the Higgsino mass parameter, we show that the contribution to the neutrino masses at the EW scale from dimension-six operators arising from the Kaehler potential, is suppressed relative to the Weinberg-type dimension-five operators.

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arXiv2011

On 'Light' Fermions and Proton Stability in 'Big Divisor' D3/D7 Swiss Cheese Phenomenology

Building up on our earlier work [1,2], we show the possibility of generating "light" fermion mass scales of MeV-GeV range (possibly related to first two generations of quarks/leptons) as well as eV (possibly related to first two generations of neutrinos) in type IIB string theory compactified on Swiss-Cheese orientifolds in the presence of a mobile space-time filling D3-$brane restricted to (in principle) stacks of fluxed D7-branes wrapping the "big" divisor Σ_B. This part of the paper is an expanded version of the latter half of section 3 of a published short invited review [3] written up by one of the authors [AM]. Further, we also show that there are no SUSY GUT-type dimension-five operators corresponding to proton decay, as well as estimate the proton lifetime from a SUSY GUT-type four-fermion dimension-six operator to be 10^{61} years. Based on GLSM calculations in [1] for obtaining the geometric Kaehler potential for the "big divisor", using further the Donaldson's algorithm, we also briefly discuss in the first of the two appendices, obtaining a metric for the Swiss-Cheese Calabi-Yau used, that becomes Ricci flat in the large volume limit.

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arXiv2010

"Big" Divisor D3/D7 Swiss Cheese Phenomenology

We review progress made over the past couple of years in the field of Swiss Cheese Phenomenology involving a mobile space-time filling D3-brane and stack(s) of fluxed D7-branes wrapping the "big" (as opposed to the "small") divisor in (the orientifold of a) Swiss-Cheese Calabi-Yau. The topics reviewed include reconciliation of large volume cosmology and phenomenology, evaluation of soft supersymmetry breaking parameters, one-loop RG-flow equations' solutions for scalar masses, obtaining fermionic (possibly first two generations' quarks/leptons) mass scales in the O(MeV-GeV)-regime as well as (first two generations') neutrino masses (and their one-loop RG flow) of around an eV. The heavy sparticles and the light fermions indicate the possibility of "split SUSY" large volume scenario.

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arXiv2010

Soft SUSY Breaking Parameters and RG Running of Squark and Slepton Masses in Large Volume Swiss Cheese Compactifications

We consider type IIB large volume compactifications involving orientifolds of the Swiss-Cheese Calabi-Yau WCP^4[1; 1; 1; 6; 9] with a single mobile space-time filling D3-brane and stacks of D7-branes wrapping the "big" divisor (as opposed to the "small" divisor usually done in the literature thus far) as well as supporting D7-brane fluxes. After reviewing our proposal of [1] for resolving a long-standing tension between large volume cosmology and phenomenology pertaining to obtaining a 10^12 GeV gravitino in the inflationary era and a TeV gravitino in the present era, and summarizing our results of [1] on soft supersymmetry breaking terms and open-string moduli masses, we discuss the one-loop RG running of the squark and slepton masses in mSUGRA-like models (using the running of the gaugino masses) to the EW scale in the large volume limit. Phenomenological constraints and some of the calculated soft SUSY parameters identify the D7-brane Wilson line moduli as the first two generations/families of squarks and sleptons and the D3-brane (restricted to the big divisor) position moduli as the two Higgses for MSSM-like models at TeV scale. We also discuss how the obtained open-string/matter moduli make it easier to impose FCNC constraints, as well as RG flow of off-diagonal squark mass(-squared) matrix elements.

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arXiv2009

"Finite" Non-Gaussianities and Tensor-Scalar Ratio in Large Volume Swiss-Cheese Compactifications

Developing on the ideas of (section 4 of) [1] and [2] and using the formalisms of [3] and [4], after inclusion of perturbative and non-perturbative alpha' corrections to the Kaehler potential and (D1- and D3-) instanton generated superpotential, we show the possibility of getting finite values for the non-linear parameter f_{NL} while looking for non-Gaussianities in type IIB compactifications on orientifolds of the Swiss Cheese Calabi-Yau WCP^4[1,1,1,6,9] in the L(arge) V(olume) S(cenarios) limit. First we show that in the context of multi-field slow-roll inflation, for the Calabi-Yau volume V~10^5 and D3-instanton number n^s~10 along with N_e~18, one can realize f_{NL}~0.03, and for Calabi-Yau volume V~10^6 with D3-instanton number n^s~10 resulting in number of e-foldings N_e~60, one can realize f_{NL}~0.01. Further we show that with the slow-roll conditions violated and for the number of the D3-instanton wrappings n^s ~O(1), one can realize f_{NL} ~O(1). Using general considerations and some algebraic geometric assumptions, we show that with requiring a "freezeout" of curvature perturbations at super horizon scales, it is possible to get tensor-scalar ratio r ~O(10^{-3}) with the loss of scale invariance |n_R-1|=0.01 and one can obtain f_{NL} ~O(10^{-2}) as well in the context of slow-roll inflation scenarios in the same Swiss-Cheese setup. For all our calculations the large values of the genus-zero Gopakumar-Vafa invariants for compact projective varieties, play in important role. We also make some observations pertaining to the possibility of the axionic inflaton also being a cold dark matter candidate as well as a quintessence field used for explaining dark energy.

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arXiv2009

Swiss Cheese D3-D7 Soft SUSY Breaking

In type IIB large volume compactifications involving orientifolds of the Swiss-Cheese Calabi-Yau [11169] with a single mobile space-time filling D3-brane and stacks of D7-branes wrapping the "big" divisor (D_5) and supporting D7-brane fluxes, (i) using the toric data and GLSM techniques, we obtain the geometric Kaehler potential for D_5 in terms of genus-two Siegel theta functions; (ii) we show that as the D3-brane moves from a particular embedded non-singular elliptic curve to another one, it is possible to obtain 10^{12}GeV gravitino during the inflationary era as well as a TeV gravitino in the present era, for the same vol(CY)~10^6l_s^6; (iii) by constructing local appropriate involutively-odd harmonic one-form on D_5 that lies in the cokernel of the pullback of the immersion map, we show that it is possible to obtain an O(1) g_{YM} from the wrapping of D7-branes on D_5 due to competing contributions from the Wilson line moduli relative to the divisor volume modulus (to permit gaugino condensation [gc], we consistently consider zero sections of ND_5) - to simplify we restrict the D3-brane to D_5 which means W_gc=0; (iv) we obtain gaugino masses of the order of gravitino mass and the matter fields' masses to be enhanced relative to the gravitino mass; (v) the anomaly-mediated gaugino masses are found to be suppressed relative to the gravity-mediated gaugino masses by the standard loop factor; (vi) new sub-dominant mu-terms are obtained from section of the (small) divisor bundle encoding information about the ED3- instanton fluctuation determinant; (vii) we obtain a (near)universality in the masses, hat(mu), hat(Y) and the hat(mu)B-terms for the D3 position moduli and a hierarchy in the same set and a universality in the A-terms on inclusion of D7 Wilson line moduli.

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arXiv2008

On Issues in Swiss Cheese Compactifications

We give a brief review of our previous works: [1,2]. We discuss two sets of issues. The first has to do with the possibility of getting a non-supersymmetric dS minimum without the addition of anti-D3 branes as in KKLT, and axionic slow-roll inflation, in type II flux compactifications. The second has to do with the "Inverse Problem" [3] and "Fake Superpotentials" [4] for extremal (non)supersymmetric black holes in type II compactifications. We use (orientifold of) a "Swiss Cheese" Calabi-Yau [5] expressed as a degree-18 hypersurface in WCP^4[1,1,1,6,9] in the "large-volume-scenario" limit [6] for the former.

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arXiv2008

Large Volume Axionic Swiss-Cheese Inflation

Continuing with the ideas of (section 4 of) [1], after inclusion of perturbative and non-perturbative alpha' corrections to the Kaehler potential and (D1- and D3-) instanton generated superpotential, we show the possibility of slow-roll axionic inflation in the large volume limit of Swiss-Cheese Calabi-Yau orientifold compactifications of type IIB string theory. We also include one- and two-loop corrections to the Kaehler potential but find the same to be subdominant to the (perturbative and non-perturbative) alpha' corrections. The NS-NS axions provide a flat direction for slow-roll inflation to proceed from a saddle point to the nearest dS minimum.

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arXiv2008

Moduli Stabilization, Large-Volume dS Minimum Without anti-D3-Branes, (Non-)Supersymmetric Black Hole Attractors and Two-Parameter Swiss Cheese Calabi-Yau's

We consider issues of moduli stabilization and "area codes" for type II flux compactifications, and the "Inverse Problem" and "Fake Superpotentials" for extremal (non)supersymmetric black holes in type II compactifications on (orientifold of) a compact two-parameter Calabi-Yau expressed as a degree-18 hypersurface in WCP^4[1,1,1,6,9] which has multiple singular loci in its moduli space. We argue the existence of extended "area codes" [1] wherein for the same set of large NS-NS and RR fluxes, one can stabilize all the complex structure moduli and the axion-dilaton modulus (to different sets of values) for points in the moduli space away as well as near the different singular conifold loci leading to the existence of domain walls. Using techniques of [3] we explicitly show that given a set of moduli and choice of a gauge(the superpotential) corresponding to an extremal black hole, one can actually work out the corresponding charges (of the extremal black hole) - the so-called "inverse problem". We also show the existence of "fake superpotentials" [4] corresponding to non-BPS extremal black-hole solutions corresponding to the aforementioned Calabi-Yau three-fold. By including non-perturbative alpha' and instanton corrections in the Kaehler potential and superpotential [2], we show the possibility of getting a large-volume non-supersymmetric (A)dS minimum - a dS minimum without the addition of anti-D3 branes a la KKLT. The chosen Calabi-Yau has been of relevance also from the point of other studies of stabilization of the Kaehler moduli via nonperturbative instanton contributions [5] and the possibility of getting non-supersymmetric AdS vacua (and their subsequent dS-uplifts) using (alpha')^3 corrections to the Kaehler potential [6,7,8].

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arXiv2006

Super Picard-Fuchs Equation and Monodromies for Supermanifolds

Following [1] and [2], we discuss the Picard-Fuchs equation for the super Landau-Ginsburg mirror to the super-Calabi-Yau in WCP^(3|2)[1,1,1,3|1,5], (using techniques of [3,4]) Meijer basis of solutions and monodromies (at 0,1 and \infty) in the large and small complex structure limits, as well as obtain the mirror hypersurface, which in the large Kaehler limit, turns out to be either a bidegree-(6,6) hypersurface in WCP^(3|1)[1,1,1,2] x WCP^(1|1)[1,1|6] or a (Z_2-singular) bidegree-(6,12) hypersurface in WCP^(3|1)[1,1,2,6|6] x WCP^(1|1)[1,1|6].

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arXiv2006

Supersymmetry of Noncompact MQCD-like Membrane Instantons and Heat Kernel Asymptotics

We perform a heat kernel asymptotics analysis of the nonperturbative superpotential obtained from wrapping of an M2-brane around a supersymmetric noncompact three-fold embedded in a (noncompact) G_2-manifold as obtained in [1], the three-fold being the one relevant to domain walls in Witten's MQCD [2], in the limit of small "zeta", a complex constant that appears in the Riemann surfaces relevant to defining the boundary conditions for the domain wall in MQCD. The MQCD-like configuration is interpretable, for small but non-zero zeta as a noncompact/"large" open membrane instanton, and for vanishing zeta, as the type IIA D0-brane (for vanishing M-theory cicle radius). We find that the eta-function Seeley de-Witt coefficients vanish, and we get a perfect match between the zeta-function Seeley de-Witt coefficients (up to terms quadratic in zeta) between the Dirac-type operator and one of the two Laplace-type operators figuring in the superpotential. This is an extremely strong signature of residual supersymmetry for the nonperturbative configurations in M-theory considered in this work.

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arXiv2006

On the Existence of Non-Supersymmetric Black Hole Attractors for Two-Parameter Calabi-Yau's and Attractor Equations

We look for possible nonsupersymmetric black hole attractor solutions for type II compactification on (the mirror of) CY_3(2,128) expressed as a degree-12 hypersurface in WCP^4[1,1,2,2,6]. In the process, (a) for points away from the conifold locus, we show that the attractors could be connected to an elliptic curve fibered over C^8 which may also be "arithmetic" (in some cases, it is possible to interpret the extremization conditions as an endomorphism involving complex multiplication of an arithmetic elliptic curve), and (b) for points near the conifold locus, we show that the attractors correspond to a version of A_1-singularity in the space Image(Z^6-->R^2/Z_2(embedded in R^3)) fibered over the complex structure moduli space. The potential can be thought of as a real (integer) projection in a suitable coordinate patch of the Veronese map: CP^5-->CP^{20}, fibered over the complex structure moduli space. We also discuss application of the equivalent Kallosh's attractor equations for nonsupersymmetric attractors and show that (a) for points away from the conifold locus, the attractor equations demand that the attractor solutions be independent of one of the two complex structure moduli, and (b) for points near the conifold locus, the attractor equations imply switching off of one of the six components of the fluxes. Both these features are more obvious using the atractor equations than the extremization of the black hole potential.

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arXiv2006

Flow Equations for Uplifting Half-Flat to Spin(7) Manifolds

In this short supplement to [1], we discuss the uplift of half-flat six-folds to Spin(7) eight-folds by fibration of the former over a product of two intervals. We show that the same can be done in two ways - one, such that the required Spin(7) eight-fold is a double G_2 seven-fold fibration over an interval, the G_2 seven-fold itself being the half-flat six-fold fibered over the other interval, and second, by simply considering the fibration of the half-flat six-fold over a product of two intervals. The flow equations one gets are an obvious generalization of the Hitchin's flow equations (to obtain seven-folds of G_2 holonomy from half-flat six-folds [2]). We explicitly show the uplift of the Iwasawa using both methods, thereby proposing the form of the new Spin(7) metrics. We give a plausibility argument ruling out the uplift of the Iwasawa manifold to a Spin(7) eight fold at the "edge", using the second method. For $Spin(7)$ eight-folds of the type $X_7\times S^1$, $X_7$ being a seven-fold of SU(3) structure, we motivate the possibility of including elliptic functions into the "shape deformation" functions of seven-folds of SU(3) structure of [1] via some connections between elliptic functions, the Heisenberg group, theta functions, the already known $D7$-brane metric [3] and hyper-Kähler metrics obtained in twistor spaces by deformations of Atiyah-Hitchin manifolds by a Legendre transform in [4].

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