2,051 research outputs found
Phase diagram of an extended quantum dimer model on the hexagonal lattice
We introduce a quantum dimer model on the hexagonal lattice that, in addition
to the standard three-dimer kinetic and potential terms, includes a competing
potential part counting dimer-free hexagons. The zero-temperature phase diagram
is studied by means of quantum Monte Carlo simulations, supplemented by
variational arguments. It reveals some new crystalline phases and a cascade of
transitions with rapidly changing flux (tilt in the height language). We
analyze perturbatively the vicinity of the Rokhsar-Kivelson point, showing that
this model has the microscopic ingredients needed for the "devil's staircase"
scenario [E. Fradkin et al., Phys. Rev. B 69, 224415 (2004)], and is therefore
expected to produce fractal variations of the ground-state flux.Comment: Published version. 5 pages + 8 (Supplemental Material), 31
references, 10 color figure
Entanglement scaling in critical two-dimensional fermionic and bosonic systems
We relate the reduced density matrices of quadratic bosonic and fermionic
models to their Green's function matrices in a unified way and calculate the
scaling of bipartite entanglement of finite systems in an infinite universe
exactly. For critical fermionic 2D systems at T=0, two regimes of scaling are
identified: generically, we find a logarithmic correction to the area law with
a prefactor dependence on the chemical potential that confirms earlier
predictions based on the Widom conjecture. If, however, the Fermi surface of
the critical system is zero-dimensional, we find an area law with a
sublogarithmic correction. For a critical bosonic 2D array of coupled
oscillators at T=0, our results show that entanglement follows the area law
without corrections.Comment: 4 pages, 4 figure
Transfer ideals and torsion in the Morava -theory of abelian groups
Let be a finite abelian group of rank at least . We show that , the quotient of the Morava -cohomology of by the ideal generated by the image of the transfers along all proper subgroups, contains -torsion. The proof makes use of transchromatic character theory
The Superluminal Character of the Compact Steep Spectrum Quasar 3C 216
We report the results of fourth epoch VLBI observations at 4990.99 MHz, with a resolution of ~1 mas, of the compact steep-spectrum quasar 3C216. Superluminal motion in this object is confirmed. Although a constant superluminal expansion at v_(app) = 3.9c ± 0.6 is not ruled out, our four epoch data are suggestive of component deceleration. In this paper we discuss the possibility of deceleration taking into account the compact steep spectrum nature of this quasar. We conclude that (a) compact steep spectrum sources may show the same beaming and orientation phenomena as extended sources and (b) the compact steep spectrum nature of the source could offer an explanation for the possible deceleration
Chromatic fracture cubes
In this note, we construct a general form of the chromatic fracture cube, using a convenient characterization of the total homotopy fiber, and deduce a decomposition of the E(n)-local stable homotopy category
On conjectures of Hovey-Strickland and Chai
We prove the height two case of a conjecture of Hovey and Strickland that provides a -local analogue of the Hopkins--Smith thick subcategory theorem. Our approach first reduces the general conjecture to a problem in arithmetic geometry posed by Chai. We then use the Gross--Hopkins period map to verify Chai's Hope at height two and all primes. Along the way, we show that the graded commutative ring of completed cooperations for Morava -theory is coherent, and that every finitely generated Morava module can be realized by a -local spectrum as long as . Finally, we deduce consequences of our results for descent of Balmer spectra
- …