348 research outputs found
Educational Psychology in the Virtual World: A Small Study on Practice Adaptations During the COVID-19 Pandemic and Potential Benefits for Future Services
Educational psychologists (EPs) have made significant adaptations to their practice during the COVID-19 pandemic due to educational and practice restrictions in England. These adaptations, whilst facing many challenges, have also presented opportunities for growth within the profession. The current study gained a small group of EPs’ views of their experiences of working remotely through the completion of an online questionnaire. Subsequent data analysis found that EPs increased their confidence working remotely and using technology during the pandemic. The main changes reported by the participating EPs related to how they accessed clients and adapted their practice to suit remote working. Personal and professional successes were identified, and many EPs indicated it would be useful to continue some elements of remote working following the pandemic. An important area for future exploration would be to further investigate the benefits of remote working and gain the views of other stakeholders regarding their experiences of remote EP practice
Anomalous tunneling of bound pairs in crystal lattices
A novel method of solving scattering problems for bound pairs on a lattice is
developed. Two different break ups of the hamiltonian are employed to calculate
the full Green operator and the wave function of the scattered pair. The
calculation converges exponentially in the number of basis states used to
represent the non-translation invariant part of the Green operator. The method
is general and applicable to a variety of scattering and tunneling problems. As
the first application, the problem of pair tunneling through a weak link on a
one-dimensional lattice is solved. It is found that at momenta close to \pi the
pair tunnels much easier than one particle, with the transmission coefficient
approaching unity. This anomalously high transmission is a consequence of the
existence of a two-body resonant state localized at the weak link.Comment: REVTeX, 5 pages, 4 eps figure
Hidden dimers and the matrix maps: Fibonacci chains re-visited
The existence of cycles of the matrix maps in Fibonacci class of lattices is
well established. We show that such cycles are intimately connected with the
presence of interesting positional correlations among the constituent `atoms'
in a one dimensional quasiperiodic lattice. We particularly address the
transfer model of the classic golden mean Fibonacci chain where a six cycle of
the full matrix map exists at the centre of the spectrum [Kohmoto et al, Phys.
Rev. B 35, 1020 (1987)], and for which no simple physical picture has so far
been provided, to the best of our knowledge. In addition, we show that our
prescription leads to a determination of other energy values for a mixed model
of the Fibonacci chain, for which the full matrix map may have similar cyclic
behaviour. Apart from the standard transfer-model of a golden mean Fibonacci
chain, we address a variant of it and the silver mean lattice, where the
existence of four cycles of the matrix map is already known to exist. The
underlying positional correlations for all such cases are discussed in details.Comment: 14 pages, 2 figures. Submitted to Physical Review
Lattice thermal conductivity of pristine and doped (B,N) Graphene
In this paper, the effect of B and N doping on the phonon induced thermal
conductivity of graphene has been investigated. This study is important when
one has to evaluate the usefulness of electronic properties of B and N doped
graphene. We have performed the calculations by employing density functional
perturbation theory(DFPT) to calculate the inter-atomic forces=force constants
of pristine/doped graphene. Thermal conductivity calculations have been carried
out by making use of linearized Boltzmann transport equations (LBTE) under
single-mode relaxation time approximation (RTA). The thermal conductivity of
pristine graphene has been found to be of the order of 4000W/mK at 100K, which
decreases gradually with an increase in temperature. The thermal conductivity
decreases drastically by 96 % to 190 W/mK when doped with 12.5 % B and reduces
by 99 % to 30 W/mK with 25 % B doping. When graphene is doped with N, the
thermal conductivity decreases to 4 W/mK and 55 W/mK for 12.5 % and 25 % doping
concentration, respectively. We have found that the thermal conductivity of
doped graphene show less sensitivity to change in temperature. It has also been
shown that the thermal conductivity of graphene can be tuned with doping and
has a strong dependence on doping concentration.Comment: Accepted for publication in Material Research Expres
Charge and spin density response functions of the clean two-dimensional electron gas with Rashba spin-orbit coupling at finite momenta and frequencies
We analytically evaluate charge and spin density response functions of the
clean two-dimensional electron gas with Rashba spin-orbit coupling at finite
momenta and frequencies. On the basis of our exact expressions we discuss the
accuracy of the long-wavelength and the quasiclassical approximations. We also
derive the static limit of spin susceptibilities and demonstrate, in
particular, how the Kohn-like anomalies in their derivatives are related to the
spin-orbit modification of the Ruderman-Kittel-Kasuya-Yosida interaction.
Taking into account screening and exchange effects of the Coulomb interaction,
we describe the collective charge and spin density excitation modes which
appear to be coupled due to nonvanishing spin-charge response function.Comment: 15 pages, 9 figure
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