In
a generic quantum experiment we have a given set of devices analyzing some
physical property of a system. To each device involved in the experiment we
associate a set of random outcomes corresponding to the possible values of the
variable analyzed by the device. Devices have apertures that permit physical
systems to pass through them. Each aperture is labelled as "input" or
"output" depending on whether it is assumed that the aperture lets
the system go inside or outside the device. Assuming a particular input/output
structure for the devices involved in a generic experiment is equivalent to
assume a particular causal structure for the space-time events constituted by
the outcomes happening on devices. The joint probability distribution of these
outcomes is usually predicted assuming an absolutely defined input/output
structure of devices. This means that all observers of the experiment agree on
whether an aperture is labelled as "input" or "output". In
this talk we show that the mathematical formalism of quantum theory permits to
predict the joint probability distribution of outcomes in a generic experiment
in such a way that the input/output structure is indeed relative to an
observer. This means that two observers of the same experiment can predict the
joint probability distribution of outcomes assuming different input/output
labels for the apertures. Since input/output structure is the causal structure
of the space-time events constituting the outcomes involved in the experiment
we conclude that in quantum theory, the causal structure of events may not be
regarded as absolute but rather as relative to the observer. We finally point
out that properly extending this concept to the cosmological domain could shed
light on the problem of dark energy.
I will present recent developments in the computation of
three point functions in the AdS4/CFT3 correspondence. More specifically I will
consider two different computations for three point functions of operators
belonging to the SU(2)XSU(2) sector of ABJM. I
will discuss first the generalization of the
determinant representation, found by Foda for the three-point functions of
the SU(2) sector of N = 4 SYM, to the ABJM theory and
secondly semiclassical
computations in the case where two operators are heavy and one is light
and BPS, comparing the results obtained in the gauge theory
side using a coherent state description of the heavy operators with its string theory
counterpart calculated holographically.
After a brief overview of electroweak baryogenesis, I will show how to construct a solution of
the Dirac equation for a CP violating kink wall. This solution nicely reduces
to the known solution for a CP violating thin (step) wall. The novel solution can be helpful for studies
of baryogenesis sources at strong first order phase transitions, which is
relevant for electroweak scale baryogenesis studies.