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Уважаемые коллеги!<br>
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На заседании Ученого совета в пятницу 21 апреля в 11:30 будет
заслушан доклад:<br>
<br>
Геннадий Ю. Шитов (Université de Sherbrooke)<br>
<font size="4"><b>Brane order, quantum magnetism, and partition
function zeros in modulated anisotropic ladders</b></font><br>
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<div class="abstract tex">
The presentation will be focused on the recent work [1] on the
two-leg spin-1/2 ladders with anisotropy and two dimerization
patterns (columnar/staggered). This model is equivalent to a
modulated interacting fermionic Kitaev ladder. The Hartree-Fock
approximation reduces the model to a sum of two quadratic
effective Majorana Hamiltonians, which can be mapped onto two
transverse quantum XY chains. This simplifies considerably
calculations of the order parameters and analysis of the hidden
symmetry breaking. The ground-state phase diagrams are found for
each dimerization pattern. The diagrams contain phases with
conventional antiferromagnetism, as well all those with non-local
brane orders. We found
analytically all the magnetizations and brane order parameters for
the staggered case, as functions of couplings of the effective
Hamiltonian, while the brane order parameters of the columnar
ladder are found numerically from the Toeplitz determinants. The
quantum phase transitions, disorder lines, ground-state
factorization (disentanglement), and the additional attributes of
topological order such as winding numbers and edge Majorana
states, are shown to be determined by zeros of the partition
function.
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1. T. Pandey and G.Y. Chitov, Phys. Rev. B 106, 094413 (2022).
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ID и пароль онлайн-трансляций в Zoom те же, что и для предыдущих
трансляций докладов на Ученом совете:<br>
<div class="moz-cite-prefix"> <a class="moz-txt-link-freetext"
href="https://zoom.us/j/96899364518?pwd=MzBsR2lYT0lYL2x2b1oyNU9LeWlWUT09">https://zoom.us/j/96899364518?pwd=MzBsR2lYT0lYL2x2b1oyNU9LeWlWUT09</a><br>
Meeting ID: 968 9936 4518<br>
Пароль: 250319</div>
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