6,707 research outputs found
Non-Hermitian von Roos Hamiltonian's -weak-pseudo-Hermiticity, isospectrality and exact solvability
A complexified von Roos Hamiltonian is considered and a Hermitian first-order
intertwining differential operator is used to obtain the related position
dependent mass -weak-pseudo-Hermitian Hamiltonians. Using a
Liouvillean-type change of variables, the -weak-pseudo-Hermitian von Roos
Hamiltonians H(x) are mapped into the traditional Schrodinger Hamiltonian form
H(q), where exact isospectral correspondence between H(x) and H(q) is obtained.
Under a user-friendly position dependent mass settings, it is observed that for
each exactly-solvable -weak-pseudo-Hermitian reference-Hamiltonian
H(q)there is a set of exactly-solvable -weak-pseudo-Hermitian isospectral
target-Hamiltonians H(x). A non-Hermitian PT-symmetric Scarf II and a
non-Hermitian periodic-type PT-symmetric Samsonov-Roy potentials are used as
reference models and the corresponding -weak-pseudo-Hermitian isospectral
target-Hamiltonians are obtained.Comment: 11 pages, no figures
On computing joint invariants of vector fields
A constructive version of the Frobenius integrability theorem -- that can be
programmed effectively -- is given. This is used in computing invariants of
groups of low ranks and recover examples from a recent paper of Boyko, Patera
and Popoyvich \cite{BPP}
Market Structure, Inflation, and Price Dispersion
In this paper, we investigate the impact of market structure on the relationship between inflation and price dispersion. We first propose a new empirical model of the relationship between inflation and dispersion with firmer theoretical foundations, and then extend the basic model to incorporate the potential effects of market structure. We estimate the basic and market structure specifications using a unique micro-level data set from Istanbul, which consists of monthly price observations from three different store types: convenience stores, open-air markets, and supermarkets. Our empirical findings support almost all of the basic and market structure predictions.inflation, market structure, menu cost models, micro panel data, price dispersion
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