1,327 research outputs found
Construction of Many-Body Eigenstates with Displacement Transformations
Many-body eigenstates beyond the gaussian approximation can be constructed in
terms of local integrals of motion (IOM), although their actual computation has
been until now a daunting task. We present a new practical computation of IOMS
based on displacement transformations. It represents a general and systematic
way to extend Hartree-Fock and configuration interaction theories to higher
order. Our method combines minimization of energy and energy variance of a
reference state with exact diagonalization. We show that our implementation is
able to perform ground state calculations with high precision for relatively
large systems. Since it keeps track of the IMO's forming a reference state, our
method is particularly efficient dealing with excited states, both in accuracy
and the number of different states that can be constructed
Emergent Symmetry at the N\'eel to Valence-Bond-Solid Transition
We show numerically that the `deconfined' quantum critical point between the
N\'eel antiferromagnet and the columnar valence-bond-solid, for a square
lattice of spin-1/2s, has an emergent symmetry. This symmetry allows
the N\'eel vector and the valence-bond-solid order parameter to be rotated into
each other. It is a remarkable 2+1-dimensional analogue of the symmetry that appears in the scaling limit for the
spin-1/2 Heisenberg chain. The emergent is strong evidence that the
phase transition in the 2+1D system is truly continuous, despite the violations
of finite-size scaling observed previously in this problem. It also implies
surprising relations between correlation functions at the transition. The
symmetry enhancement is expected to apply generally to the critical
two-component Abelian Higgs model (non-compact model). The result
indicates that in three dimensions there is an -symmetric conformal
field theory which has no relevant singlet operators, so is radically different
to conventional Wilson-Fisher-type conformal field theories.Comment: 4+epsilon pages, 6 figure
VERTICAL TRANSMISSION OF CONSUMPTION BEHAVIOR AND THE DISTRIBUTION OF SURNAMES
This paper attempts to detect the existence of links in consumptionpreferences between generations. Preferences for consumption goods may bedetermined by the preferences of parents (vertical transmission) and/or bypreferences arising from the environment (horizontal transmission). Wepropose an indirect methodology to overcome the lack of data on consumptionchoices of dynasties, i.e., parents and their adult offspring. This new approachis based on the analysis of the correlation between the geographicaldistributions of surnames and consumption choices. Our results show that thereis horizontal transmission of preferences regarding non-food items and possiblyvertical transmission for food items.Preference formation, surnames, vertical and horizontal transmission.
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