24,221 research outputs found
Unwinding of a one-dimensional topological superconductor
We show that a topological superconductor made of four chains of
superconducting spinless fermions characterized by four Majorana edge states
can adiabatically be deformed into a trivial band insulator. To unwind this
time-reversal invariant topological superconductor, interactions to spinful
fermions are switched on along an adiabatic path. Thereby, we couple modes
which belong to two different representations of the time-reversal symmetry
operator T with T^2 = 1 and T^2 = -1, respectively. This observation can be
understood by investigating how the relevant symmetries act on the entanglement
spectrum giving rise to four instead of eight different topological phases with
Majorana edge modes. We also show that a simple level crossing of doubly and
singly degenerate states occurs in the entanglement spectrum upon deforming the
quantum state.Comment: 7 pages, substantial changes in the semantics compared to first
versio
On Path Integration on Noncommutative Geometries
We discuss a recent approach to quantum field theoretical path integration on
noncommutative geometries which imply UV/IR regularising finite minimal
uncertainties in positions and/or momenta. One class of such noncommutative
geometries arise as `momentum spaces' over curved spaces, for which we can now
give the full set of commutation relations in coordinate free form, based on
the Synge world function.Comment: 8 pages, LaTe
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