Directional detection of Dark Matter

Among the many experimental techniques available, those providing directional information have the potential of yielding an unambiguous observation of WIMPs even in the presence of insidious backgrounds. A measurement of the distribution of arrival direction of WIMPs can also discriminate between Galactic Dark Matter halo models. In this article, I will discuss the motivation for directional detectors and review the experimental techniques used by the various experiments. I will then describe one of them, the DMTPC detector, in more detail.Comment: 17 pages, 11 postscript figures, mini-review submitted to Modern Physics Letters A (MPLA). Submitted to Modern Physics Letters A (MPLA

Gaseous Dark Matter Detectors

Dark Matter detectors with directional sensitivity have the potential of yielding an unambiguous positive observation of WIMPs as well as discriminating between galactic Dark Matter halo models. In this article, we introduce the motivation for directional detectors, discuss the experimental techniques that make directional detection possible, and review the status of the experimental effort in this field.Comment: 19 pages, review on gaseous directional dark matter detectors submitted to New Journal of Physic

Ultrafast dynamics of fluctuations in high-temperature superconductors far from equilibrium

Despite extensive work on high-temperature superconductors, the critical behavior of an incipient condensate has so far been studied exclusively under equilibrium conditions. Here, we excite Bi2Sr2CaCu2O8+d with a femtosecond laser pulse and monitor the subsequent nonequilibrium dynamics of the mid-infrared conductivity. Our data allow us to discriminate temperature regimes where superconductivity is either coherent, fluctuating or vanishingly small. Above the transition temperature Tc, we make the striking observation that the relaxation to equilibrium exhibits power-law dynamics and scaling behavior, both for optimally and underdoped superconductors. Our findings can in part be modeled using time-dependent Ginzburg-Landau theory and provide strong indication of universality in systems far from equilibrium.Comment: 5 pages, 4 figure

Color loci placemaking: The urban color between needs of continuity and renewal

The article presents the theoretical framework and the operational concepts of a research, finalized to explore and verify the prerequisites of an approach to urban color that, while recognizing to color the flexible as well as transient capacity to respond to the successive and multiple demands that characterize the urban space, sees a possible way of coexisting between the needs of continuity and renewal. Searching to understand the modalities and possibilities through which colour can intervene in the processes of transformation of the city to support both the needs of resignification and reappropriation and those of conservation and enhancement of the vital identity of each single place, the research looked on one side to the experiences gained within the colour plans and Lenclos' geography of colour and on the other side to the different and diversified experiences developed within the idea and practice of placemaking, aimed at the recognition and enhancement of the collective and plural creative dimension that colour seems effectively able to interpret. The term “color loci placemaking” was introduced to summarize this mode/possibility of understanding and approaching urban color, characterized especially by the attention for the specificity of each single place and the human factor underpinning place‐experience

DMTPC: A dark matter detector with directional sensitivity

By correlating nuclear recoil directions with the Earth's direction of motion through the Galaxy, a directional dark matter detector can unambiguously detect Weakly Interacting Massive Particles (WIMPs), even in the presence of backgrounds. Here, we describe the Dark Matter Time-Projection Chamber (DMTPC) detector, a TPC filled with CF4 gas at low pressure (0.1 atm). Using this detector, we have measured the vector direction (head-tail) of nuclear recoils down to energies of 100 keV with an angular resolution of <15 degrees. To study our detector backgrounds, we have operated in a basement laboratory on the MIT campus for several months. We are currently building a new, high-radiopurity detector for deployment underground at the Waste Isolation Pilot Plant facility in New Mexico.Comment: 4 pages, 2 figures, proceedings for the CIPANP 2009 conference, May 26-31, 200

On quantum mean-field models and their quantum annealing

This paper deals with fully-connected mean-field models of quantum spins with p-body ferromagnetic interactions and a transverse field. For p=2 this corresponds to the quantum Curie-Weiss model (a special case of the Lipkin-Meshkov-Glick model) which exhibits a second-order phase transition, while for p>2 the transition is first order. We provide a refined analytical description both of the static and of the dynamic properties of these models. In particular we obtain analytically the exponential rate of decay of the gap at the first-order transition. We also study the slow annealing from the pure transverse field to the pure ferromagnet (and vice versa) and discuss the effect of the first-order transition and of the spinodal limit of metastability on the residual excitation energy, both for finite and exponentially divergent annealing times. In the quantum computation perspective this quantity would assess the efficiency of the quantum adiabatic procedure as an approximation algorithm.Comment: 44 pages, 23 figure

Quantum Quench in the Transverse Field Ising chain I: Time evolution of order parameter correlators

We consider the time evolution of order parameter correlation functions after a sudden quantum quench of the magnetic field in the transverse field Ising chain. Using two novel methods based on determinants and form factor sums respectively, we derive analytic expressions for the asymptotic behaviour of one and two point correlators. We discuss quenches within the ordered and disordered phases as well as quenches between the phases and to the quantum critical point. We give detailed account of both methods.Comment: 65 pages, 21 figures, some typos correcte

New Particles Working Group Report of the Snowmass 2013 Community Summer Study

This report summarizes the work of the Energy Frontier New Physics working group of the 2013 Community Summer Study (Snowmass)

Theoretical Overview: The New Mesons

After commenting on the state of contemporary hadronic physics and spectroscopy, I highlight four areas where the action is: searching for the relevant degrees of freedom, mesons with beauty and charm, chiral symmetry and the D_{sJ} levels, and X(3872) and the lost tribes of charmonium.Comment: 10 pages, uses jpconf.cls; talk at First Meeting of the APS Topical Group on Hadronic Physic