اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدDynamics of quenched topological edge modes
81
0
0.0
(
0
)
تأليف
P.D. Sacramento
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
A characteristic feature of topological systems is the presence of robust gapless edge states. In this work the effect of time-dependent perturbations on the edge states is considered. Specifically we consider perturbations that can be understood as changes of the parameters of the Hamiltonian. These changes may be sudden or carried out at a fixed rate. In general, the edge modes decay in the thermodynamic limit, but for finite systems a revival time is found that scales with the system size. The dynamics of fermionic edge modes and Majorana modes are compared. The effect of periodic perturbations is also referred allowing the appearance of edge modes out of a topologically trivial phase.
قيم البحث
اقرأ أيضاً
The fermionic and Majorana edge mode dynamics of various topological systems is compared, after a sudden global quench of the Hamiltonian parameters takes place. Attention is focused on the regimes where the survival probability of an edge state has
oscillations either due to critical or off-critical quenches. The nature of the wave functions and the overlaps between the eigenstates of different points in parameter space determine the various types of behaviors, and the distinction due to the Majorana nature of the excitations plays a lesser role. Performing a sequence of quenches it is shown that the edge states, including Majorana modes, may be switched off and on. Also, the generation of Majoranas due to quenching from a trivial phase is discussed.
Collective modes in two dimensional topological superconductors are studied by an extended random phase approximation theory while considering the influence of vector field of light. In two situations, the s-wave superconductors without spin-orbit-co
upling (SOC), and the hybrid semiconductor and s-wave superconductor layers with strong SOC, we get the analytical results for longitudinal modes which are found to be indeed gapless. Further more, the effective modes volumes can be calculated, the electric and magnetic fields can be expressed as the creation and annihilation operators of such modes. So, one can study the interaction of them with other quasi-particles through fields.
We explore Andreev states at the interface of graphene and a superconductor for a uniform pseudo-magnetic field. Near the zeroth-pseudo Landau level, we find a topological transition as a function of applied Zeeman field, at which a gapless helical m
ode appears. This 1D mode is protected from backscattering as long as intervalley- and spin-flip scattering are suppressed. We discuss a possible experimental platform to detect this gapless mode based on strained suspended membranes on a superconductor, in which dynamical strain causes charge pumping
Josephson radiation is a powerful method to probe Majorana zero modes in topological superconductors. Recently, Josephson radiation with half the Josephson frequency has been experimentally observed in a HgTe-based junction, possibly from Majorana ze
ro modes. However, this radiation vanishes above a critical voltage, sharply contradicting previous theoretical results. In this work, we theoretically obtain a radiation spectrum quantitatively in agreement with the experiment after including the nonlinear dynamics of the Majorana states into the standard resistively shunted junction model. We further predict two new structures of the radiation spectrum for future experimental verification: an interrupted emission line and a chaotic regime. We develop a fixed-point analysis to understand all these features. Our results resolve an apparent discrepancy between theory and experiments, and will inspire reexamination of structures in radiation spectra of various topological Josephson junctions.
We uncover an edge geometric phase mechanism to realize the second-order topological insulators and topological superconductors (SCs), and predict realistic materials for the realization. The theory is built on a novel result shown here that the nont
rivial pseudospin textures of edge states in a class of two-dimensional (2D) topological insulators give rise to the geometric phases defined on the edge, for which the effective edge mass domain walls are obtained across corners when external magnetic field or superconductivity is considered, and the Dirac or Majorana Kramers corner modes are resulted. Remarkably, with this mechanism we predict the Majorana Kramers corner modes by fabricating 2D topological insulator on only a uniform and conventional $s$-wave SC, in sharp contrast to the previous proposals which applies unconventional SC pairing or SC $pi$-junction. We find that Au/GaAs(111) can be a realistic material candidate for realizing such Majorana Kramers corner modes.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
