ELFT HÍRADÓ

[Janos Asboth <asboth.janos AT ttk.bme.hu>]

Meghívó

BME Elméleti Fizika Szeminárium,

márc. 14. péntek 10h15,
1111 Bp., Budafoki út 8., BME FIII. magasföldszint 1, szemináriumi szoba

Sudipto Das (BME Elm. Fiz. tanszék):
Theory of the Novel Phase of Fractional Quantum Hall States in the
Second Landau Level

The fractional quantum Hall states in the second Landau level exhibits
exotic physics; some states have even been experimentally found to
host non-Abelian quasi-particles, which could be devised as qubits for
fault-tolerant topological quantum computation. The Coulomb
interaction is the principal interaction in the fractional quantum
Hall effect, prompting the development of several theories and models
to elucidate these states over the years. However, an unresolved
debate persists between theoretical predictions and experimental
observations. In contrast to the lowest Landau level, the influence of
Landau-level mixing becomes notably pronounced at the second Landau
level, which arises in a
comparatively lower magnetic field. At a moderate range of Landau
level mixing strength, consistent with GaAs-GaAlAs systems, we find a
reentrant Anomalous phase (A-phase) that is quantized and exhibits a
substantial gap in the thermodynamic limit, being topologically
distinct from the phase associated with pure Coulomb interaction. We
propose a ground state wave function for the 5/2 state in the second
Landau level and generalize it to all experimentally observed states
in the second Landau level. These wave functions have remarkably high
overlap with the corresponding exact ground states in the A-phase and
can support non-Abelian quasiparticle excitation. We believe our
proposed wave
functions for all the second Landau level states in this A-phase
should possibly corroborate with the experimentally observed states.

References:
[1] S. Das, S. Das, and S. S. Mandal, Phys. Rev. Lett. 131, 056202 (2023).
[2] S. Das, S. Das, and S. S. Mandal, Phys. Rev. Lett. 132, 029602 (2024).
[3] S. Das, S. Das, and S. S. Mandal, Phys. Rev. Lett. 132, 106501 (2024).
[4] S. Das, S. Das, and S. S. Mandal, Phys. Rev. B 110, L121303 (2024).

Minden érdeklődőt szeretettel várunk.
Asbóth János,
 szemináriumi koordinátor