1,270 research outputs found
How far can we go with deliberative research at dangerous places?
Questions of research ethics are raised when deliberative research is done in war situations
International debt with unenforceable claims
Debts, External ; Loans, Foreign ; Banks and banking, International ; Developing countries ; Bank loans
Conformal Field Theory and Geometry of Strings
What is quantum geometry? This question is becoming a popular leitmotiv in
theoretical physics and in mathematics. Conformal field theory may catch a
glimpse of the right answer. We review global aspects of the geometry of
conformal fields, such as duality and mirror symmetry, and interpret them
within Connes' non-commutative geometry. Extended version of lectures given by
the 2nd author at the Mathematical Quantum Theory Conference, Vancouver,
Canada, August 4 to 8, 1993Comment: 44 pages, latex file, 5 references adde
Magnetohydrodynamics of Chiral Relativistic Fluids
We study the dynamics of a plasma of charged relativistic fermions at very
high temperature , where is the fermion mass, coupled to the
electromagnetic field. In particular, we derive a magneto-hydrodynamical
description of the evolution of such a plasma. We show that, as compared to
conventional MHD for a plasma of non-relativistic particles, the hydrodynamical
description of the relativistic plasma involves new degrees of freedom
described by a pseudo-scalar field originating in a local asymmetry in the
densities of left-handed and right-handed fermions. This field can be
interpreted as an effective axion field. Taking into account the chiral anomaly
we present dynamical equations for the evolution of this field, as well as of
other fields appearing in the MHD description of the plasma. Due to its
non-linear coupling to helical magnetic fields, the axion field significantly
affects the dynamics of a magnetized plasma and can give rise to a novel type
of inverse cascade
Reinterpretation of niche and fitness differences improves our understanding of species coexistence
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