The
combinatorial problems associated with the counting of black hole states in
loop quantum gravity can be analyzed by using suitable generating functions.
These not only provide very useful tools for exact computations, but can also
be used to perform an statistical analysis of the black hole degeneracy
spectrum, study the interesting substructure found in the entropy of
microscopic black holes and its asymptotic behavior for large horizon areas.
The methods that will be described are relevant for the discussion of the
thermodynamic limit for black holes in the area canonical ensemble. This is an
important issue in order to understand sub-leading corrections to the
Bekenstein-Hawking law.
When nuclear matter is heated beyond a temperature of 2 trillion
degrees, it converts into a strongly coupled plasma of quarks and
gluons, the sQGP. Experiments using highly energetic collisions
between heavy nuclei have revealed that this new state of matter is a
nearly ideal, highly opaque liquid. A description based upon string
theory and black holes in five dimensions has made the quark- gluon
plasma an iconic example of a strongly coupled quantum system. In this
lecture I will survey the observed properties of the sQGP in the light
of the latest results from RHIC and LHC. On the theoretical side, I
will discuss the thermalization and entropy production problem and
origin and role of event-by-event fluctuations.
The spectrum of the cosmic microwave background (CMB) is known to be extremely close to a perfect blackbody. However, even within standard cosmology several processes occurring in the early Universe lead to distortions of the CMB at a level that might become observable in the future. This could open an exciting new window to early Universe physics. In my talk I will then explain in more detail why the cooling of matter in the early Universe causes a negative mu- and y-type distortion and how the damping of primordial small-scale perturbations before recombination could allow placing interesting constraints on different inflationary models.
What information can be determined about a state given
just the ground state wave function?
Quantum ground states, speaking intuitively, contain
fluctuations between many of the configurations one might want to understand.
The information about them can be organized by introducing an imaginary system,
dubbed the entanglement Hamiltonian.
What light does the dynamics of this Hamiltonian (a
precise version of the notion of "zero point motion") shed on the
actual system?
I will start my discussion near critical points, where
Lorentz invariance often emerges and the entanglement Hamiltonian becomes
tractable, revealing that it exists in one dimension less than the real system.
One application is to the fluctuations of angular momentum in a spin chain.
The entanglement Hamiltonian is especially successful at
clarifying the properties of quantum phases without order, such as topological
insulators. In particular, spin chains often have no long range order due to
quantum fluctuations. Nevertheless there can be phase transitions between two
of these disordered states, suggesting the existence of a hidden order.
My main aim in the talk will be to demonstrate that the
entanglement spectrum can serve as an order parameter for these unusual transitions; this observation leads to a
classification of one-dimensional phases.
One can understand the phases of the actual system simply
by looking at the spectrum of the entanglement Hamiltonian, just as one deduces
the properties of atoms from their spectra.
I will describe a new, generic mechanism for realizing a
period of slowly-rolling inflation through the use of an analog of 'magnetic
drift.' I will demonstrate how the mechanism works through two particular
worked examples: Chromo-Natural Inflation, which exists as a purely 4D
effective theory, and a version that can appear naturally in string theory.
There are several
fundamental predictions of quantum field theory, such as Hawking radiation (i.e., black hole evaporation) or the Sauter-Schwinger effect (i.e., electron-positron pair creation out of the quantum vacuum by a strong electric field), which have so far eluded direct experimental verification.
However, it should be possible to gain some experimental access to these effects via suitable condensed matter analogues. In this talk, some possibilities for reproducing such fundamental
quantum effects in the laboratory are discussed.
We study the gravitational collapse of the axion-dilaton
system suggested by type IIB string theory in dimensions ranging from four to
ten.
We extend previous analysis concerning the role played by
the global SL(2,
R) symmetry and also we explain ,why we do have three
different assumptions(cases). We evaluate the Choptuik exponents in the
elliptic case.
Eventually we try to explain some of the open
questions for two other assumptions and future directions.