Monte Carlo study of Bose Laughlin wave function for filling factors 1/2, 1/4 and 1/6

Strongly correlated two-dimensional electronic systems subject to a perpendicular magnetic field at lowest Landau level (LLL) filling factors: 1/2, 1/4 and 1/6 are believed to be composite fermion (CF) Fermi liquid phases. Even though a Bose Laughlin wave function cannot describe these filling factors we investigate whether such a wave function provides a lower energy bound to the true CF Fermi liquid energies. By using Monte Carlo simulations in disk geometry we compute the Bose Laughlin energies and compare them to corresponding results for the spin-polarized LLL CF Fermi liquid state and avalable data from literature.We find the unexpected result that, for filling factors 1/4 and 1/6, the Bose Laughlin ground state energy is practically identical to the true CF liquid energy while this is not the case at 1/2 where the Bose Laughlin ground state energy is sizeably lower than the energy of the CF Fermi liquid state.Comment: 7 pages, 2 figures, 2 table

Efficient Estimation of Barycentered Relative Time Delays for Distant Gravitational Wave Sources

Accurate determination of gravitational wave source parameters relies on transforming between the source and detector frames. All-sky searches for continuous wave sources are computationally expensive, in part, because of barycentering transformation of time delays to a solar system frame. This expense is exacerbated by the complicated modulation induced in signal templates. We investigate approximations for determining time delays of signals received by a gravitational wave detector with respect to the solar system barycenter. A highly non-linear conventional computation is transformed into one that has a pure linear sum in its innermost loop. We discuss application of these results to determination of the maximal useful integration time of continuous wave searches

Playing outside the box:transformative works and computer games as participatory culture

The main purpose of this study is to examine the creative fan community as a paradigm of participatory culture, from a computer games perspective. A review of relevant literature is used to examine transformative works and the related subculture in its many diverse forms. The produced discussion seeks to respond to a number of questions, such as: What exactly constitutes transformative work, what is the legal status of such work, and how can it be improved? To what extent do transformative works constitute a part of the play experience and enjoyment of games? Does participation in associated creative activities influence, shape or redefine the aforementioned experience? Can transformative works be appreciated as valuable artistic pieces on their own merits, outside the communities in which they are produced? Does the existence of the transformative work benefit the wider gaming culture from an artistic, financial or other point of view

Liquid crystalline states for two-dimensional electrons in strong magnetic fields

Based on the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) theory of two-dimensional melting and the analogy between Laughlin states and the two-dimensional one-component plasma (2DOCP), we investigate the possibility of liquid crystalline states in a single Landau level (LL). We introduce many-body trial wavefunctions that are translationally invariant but posess 2-fold (i.e. {\em nematic}), 4-fold ({\em tetratic}) or 6-fold ({\em hexatic}) broken rotational symmetry at respective filling factors $\nu = 1/3$, 1/5 and 1/7 of the valence LL. We find that the above liquid crystalline states exhibit a soft charge density wave (CDW) which underlies the translationally invariant state but which is destroyed by quantum fluctuations. By means of Monte Carlo (MC) simulations, we determine that, for a considerable variety of interaction potentials, the anisotropic states are energetically unfavorable for the lowest and first excited LL's (with index $L = 0, 1$), whereas the nematic is favorable at the second excited LL ($L = 2$).Comment: 7 figures, submitted to PRB, high-quality figures available upon reques