Abdus Salam International Center For Theoretical Physics

Trieste, Italy

The Abdus Salam International Centre for Theoretical Physics is an international research institute for physical and mathematical science that operates under a tripartite agreement between the Italian Government, United Nations Educational, Scientific and Cultural Organization , and International Atomic Energy Agency . It is located near the Miramare Park, about 10 kilometres from the city of Trieste, Italy. The centre was founded in 1964 by Pakistani Nobel Laureate Abdus Salam.ICTP is part of the Trieste System, a network of national and international scientific institutes in Trieste, promoted by the Italian physicist Paolo Budinich. Wikipedia.

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Agency: GTR | Branch: NERC | Program: | Phase: Research Grant | Award Amount: 1.10M | Year: 2015

East Africa (EA) has one of the worlds fastest growing populations, with maxima around water-bodies and rapid urbanisation. Climate change is adding to existing problems increasing vulnerability of the poorest. HyCRISTAL is driven by EA priorities. EA communities rely on rainfall for food via agriculture. EAs inland lakes are rain-fed and provide water, power and fisheries. For EAs growing cities, climate impacts on water resources will affect water supply & treatment. HyCRISTAL will therefore operate in both urban & rural contexts. Change in water availability will be critical for climate-change impacts in EA, but projections are highly uncertain for rain, lakes, rivers and groundwater, and for extremes. EA Long-Rains are observed to be decreasing; while models tend to predict an increase (the EA Climate paradox) although predictions are not consistent. This uncertainty provides a fundamental limit on the utility of climate information to inform policy. HyCRISTAL will therefore make best use of current projections to quantify uncertainty in user-relevant quantities and provide ground-breaking research to understand and reduce the uncertainty that currently limits decision making. HyCRISTAL will work with users to deliver world-leading climate research quantifying uncertainty from natural variability, uncertainty from climate forcings including those previously unassessed, and uncertainty in response to these forcings; including uncertainties from key processes such as convection and land-atmopshere coupling that are misrepresented in global models. Research will deliver new understanding of the mechanisms that drive the uncertainty in projections. HyCRISTAL will use this information to understand trends, when climate-change signals will emerge and provide a process-based expert judgement on projections. Working with policy makers, inter-disciplinary research (hydrology, economics, engineering, social science, ecology and decision-making) will quantify risks for rural & urban livelihoods, quantify climate impacts and provide the necessary tools to use climate information for decision making. HyCRISTAL will work with partners to co-produce research for decision-making on a 5-40 year timescale, demonstrated in 2 main pilots for urban water and policies to enable adaptive climate-smart rural livelihoods. These cover two of three areas of need from the African Ministerial Council on Environments Comprehensive Framework of African Climate Change Programmes. HyCRISTAL has already engaged 12 partners from across EA. HyCRISTALs Advisory Board will provide a mechanism for further growing stakeholder engagement. HyCRISTAL will work with the FCFA global & regional projects and CCKE, sharing methods, tools, user needs, expertise & communication. Uniquely, HyCRISTAL will capitalise on the new LVB-HyNEWS, an African-led consortium, governed by the East African Community, the Lake Victoria Basin Commission and National Meteorological and Hydrological agencies, with the African Ministerial Conference on Meteorology as an observer. HyCRISTAL will build EA capacity directly via collaboration (11 of 25 HyCRISTAL Co-Is are African, with 9 full-time in Africa), including data collection and via targeted workshops and teaching. HyCRISTAL will deliver evidence of impact, with new and deep climate science insights that will far outlast its duration. It will support decisions for climate-resilient infrastructure and livelihoods through application of new understanding in its pilots, with common methodological and infrastructure lessons to promote policy and enable transformational change for impact-at-scale. Using a combination of user-led and science-based management tools, HyCRISTAL will ensure the latest physical science, engineering and social-science yield maximum impacts. HyCRISTAL will deliver outstanding outputs across FCFAs aims; synergies with LVB-HyNEWS will add to these and ensure longevity beyond HyCRISTAL.

Shukla P.,Abdus Salam International Center For Theoretical Physics
Journal of High Energy Physics | Year: 2016

In the context of non-geometric type II orientifold compactifications, there have been two formulations for representing the various NS-NS Bianchi-identities. In the first formulation, the standard three-form flux (H3), the geometric flux (ω) and the non-geometric fluxes (Q and R) are expressed by using the real six-dimensional indices (e.g. Hijk,ωijk,Qijk and Rijk), and this formulation has been heavily utilized for simplifying the scalar potentials in toroidal-orientifolds. On the other hand, relevant for the studies beyond toroidal backgrounds, a second formulation is utilized in which all flux components are written in terms of various involutively even/odd (2, 1)- and (1, 1)-cohomologies of the complex threefold. In the lights of recent model building interests and some observations made in [1, 2], in this article, we revisit two most commonly studied toroidal examples in detail to illustrate that the present forms of these two formulations are not completely equivalent. To demonstrate the same, we translate all the identities of the first formulation into cohomology ingredients, and after a tedious reshuffling of the subsequent constraints, interestingly we find that all the identities of the second formulation are embedded into the first formulation which has some additional constraints. In addition, we look for the possible solutions of these Bianchi identities in a detailed analysis, and we find that some solutions can reduce the size of scalar potential very significantly, and in some cases are too strong to break the no-scale structure completely. Finally, we also comment on the influence of imposing some of the solutions of Bianchi identities in studying moduli stabilization. © 2016, The Author(s).

AbdusSalam S.S.,Abdus Salam International Center For Theoretical Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

If supersymmetry (SUSY) exists in nature and is a solution to the hierarchy problem then it should be detectable at the TeV energy scale which the large hadron collider (LHC) is now exploring. One of the main goals of the LHC is the discovery or exclusion of the R-parity conserving minimal supersymmetric standard model (MSSM). So far, the SUSY search results are presented in the context of the constrained MSSM and other specific simplified SUSY models. A model-independent analysis necessarily relies on the trigger-system of the LHC detectors. By using the posterior samples of a 20-parameter MSSM, the phenomenological MSSM, from a fit to indirect collider and cosmological data we find that there is a significant volume in the MSSM parameter space that would escape the standard trigger-systems of the detectors. As such, in the absence of discovery in the current and future LHC runs, it would be difficult if not impossible to exclude the MSSM unless some dedicated and special triggers are commissioned or a Higgs boson with mass as predicted by the supersymmetric models is not found. © 2011 Elsevier B.V.

Mussardo G.,International School for Advanced Studies | Mussardo G.,Abdus Salam International Center For Theoretical Physics
Physical Review Letters | Year: 2013

The infinite-time average of the expectation values of local fields of any interacting quantum theory after a global quench process are key quantities for matching theoretical and experimental results. For quantum integrable field theories, we show that they can be obtained by an ensemble average that employs a particular limit of the form factors of local fields and quantities extracted by the generalized Bethe ansatz. © 2013 American Physical Society.

Abdussalam S.S.,Abdus Salam International Center For Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The ATLAS Collaboration published supersymmetry limits based on up to about 4.7 fb-1 data collected over the year 2011 from LHC runs at 7 TeV. These were mainly interpreted within restricted, particular or simplified models for supersymmetry breaking schemes or scenarios. The phenomenological MSSM (pMSSM) is an alternative and more generic supersymmetry framework that captures broader phenomenological features. Searching for more generic conclusions from the supersymmetry limits interpretation, we update a Bayesian global fit of the pMSSM to pre-LHC data using the LHC-7 limits. The posterior distributions show the most up-to-date features, revealing allowed versus excluded regions in sparticle mass planes within the MSSM. © 2013 American Physical Society.

Boubekeur L.,Abdus Salam International Center For Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Tensor modes in the cosmic microwave background are one of the most robust signatures of inflation. We derive theoretical bounds on the tensor fraction, as a generalization of the well-known Lyth bound. Under reasonable assumptions, the new bounds are at least 2 orders of magnitude stronger than the original one. We comment on a previously derived generalization, the so-called Efstathiou-Mack relationship. We also derive a new absolute upper bound on tensors using de Sitter entropy bounds. © 2013 American Physical Society.

Polkovnikov A.,Boston University | Sengupta K.,Indian Association for The Cultivation of Science | Silva A.,Abdus Salam International Center For Theoretical Physics | Vengalattore M.,Cornell University
Reviews of Modern Physics | Year: 2011

This Colloquium gives an overview of recent theoretical and experimental progress in the area of nonequilibrium dynamics of isolated quantum systems. There is particularly a focus on quantum quenches: the temporal evolution following a sudden or slow change of the coupling constants of the system Hamiltonian. Several aspects of the slow dynamics in driven systems are discussed and the universality of such dynamics in gapless systems with specific focus on dynamics near continuous quantum phase transitions is emphasized. Recent progress on understanding thermalization in closed systems through the eigenstate thermalization hypothesis is also reviewed and relaxation in integrable systems is discussed. Finally key experiments probing quantum dynamics in cold atom systems are overviewed and put into the context of our current theoretical understanding. © 2011 American Physical Society.

Hardy E.,Abdus Salam International Center For Theoretical Physics
Journal of High Energy Physics | Year: 2015

Abstract: We study theories which naturally select a vacuum with parametrically small Electroweak Scale due to finite temperature effects in the early universe. In particular, there is a scalar with an approximate shift symmetry broken by a technically natural small coupling to the Higgs, and a temperature dependent potential. As the temperature of the universe drops, the scalar follows the minimum of its potential altering the Higgs mass squared parameter. The scalar also has a periodic potential with amplitude proportional to the Higgs expectation value, which traps it in a vacuum with a small Electroweak Scale. The required temperature dependence of the potential can occur through strong coupling effects in a hidden sector that are suppressed at high temperatures. Alternatively, it can be generated perturbatively from a one-loop thermal potential. In both cases, for the scalar to be displaced, a hidden sector must be reheated to temperatures significantly higher than the visible sector. However this does not violate observational constraints provided the hidden sector energy density is transferred to the visible sector without disrupting big bang nucleosynthesis. We also study how the mechanism can be implemented when the visible sector is completed to the Minimal Supersymmetric Standard Model at a high scale. Models with a UV cutoff of 10 TeV and no fields taking values over a range greater than 1012 GeV are possible, although the scalar must have a range of order 108 times the effective decay constant in the periodic part of its potential. © 2015, The Author(s).

Creminelli P.,Abdus Salam International Center For Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

In inflationary models where the source of scalar perturbations is not the inflaton, but one or more scalars with negligible coupling with the inflaton, the resulting perturbations are not only scale invariant, but fully conformally invariant with conformal dimension close to zero. This is closely related to the fact that correlation functions can only depend on the de Sitter-invariant distances. These properties follow from the isometries of the inflationary de Sitter space and are thus completely independent of the dynamics. The 3-point function is fixed in terms of two constants, while the 4-point function is a function of two parameters (instead of five as in the absence of conformal invariance). The conformal invariance of correlators can be directly checked in Fourier space, as we show in an explicit example. A detection of a nonconformal correlation function, for example, an equilateral 3-point function, would imply that the source of perturbations is not decoupled from the inflaton. © 2012 American Physical Society.

Muller M.,Abdus Salam International Center For Theoretical Physics | Wyart M.,New York University
Annual Review of Condensed Matter Physics | Year: 2015

We revisit the concept of marginal stability in glasses and determine its range of applicability in the context of an avalanche-type response to slow external driving. We argue that there is an intimate connection between a pseudogap in the distribution of local fields and crackling in systems with long-range interactions. We classify glassy systems according to the presence or absence of marginal stability, providing a unifying perspective on the phenomenology of systems as diverse as spin and electron glasses, hard spheres, pinned elastic interfaces, and soft amorphous solids undergoing plastic deformation. © 2015 by Annual Reviews.

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