Welcome

My group is part of the Condensed Matter Theory Group in BGU’s Department of Physics.

My research interests include topological states of matter, exotic superconductivity, properties of vortices, quantum Hall effects, cold atoms, Majorana fermions, fractional statistics; and the harnessing of these ideas towards topological quantum computation.

I am currently seeking MSc and PhD students to fill several positions.
There is also a post-doctoral position available (see my group page).

Research

Current Research

Microwave transitions as a signature of coherent parity mixing effects in the Majorana-Transmon qubit

Coupling Majorana fermion excitations to coherent external fields is an important stage towards their manipulation and detection. We analyse the charge and transmon regimes of a topological nano-wire embedded within a Cooper-Pair-Box, where the superconducting phase difference is coupled to the zero energy parity states that arise from Majorana quasi-particles. We show that at special gate bias points, the photon-qubit coupling can be switched off via quantum interference, and in other points it is exponentially dependent on the control parameter EJ/EC . As well as a probe for topological-superconductor excitations, we propose that this type of device could be used to realise a tunable high coherence four-level system in the superconducting circuits architecture.

Publications

• E. Ginossar and E. Grosfeld, Nature Communications 5, 4772 (2014), htto://doi.org/10.1038/ncomms5772
• K. Yavilberg, E. Ginossar and E. Grosfeld, Phys. Rev. B 92, 075143 (2015), https://doi.org/10.1103/PhysRevB.92.075143

Past Research

On the effective theory of vortices in two-dimensional spinless chiral p-wave superfluid

We propose a U(1)xZ2 effective gauge theory for vortices in a px+ipy superfluid in two dimensions. The combined gauge transformation binds U(1) and Z2 defects so that the total transformation remains single-valued and manifestly preserves the particle-hole symmetry of the action. The Z2 gauge field introduces a complete Chern-Simmons term in addiction to a partial one associated with the U(1) gauge fiel. The theory reproduces the known physics vortex dynamics such as a Magnus force proportional to the superfluid density. It also predicts a universal Abelian phase, exp(iπ/8) upon the exchange of two vortices, modified by non-universal corrections due to the partial Chern-Simon term that are screened in a charged superfluid.

Majorana fermion zero modes carried by solitons and detection of non-abelian statistics

Josephson vortices are phase solitons living in thin insulators separating two superconductors. For topological superconductors, we have recently shown that each soliton carries a single localized Majorana zero mode bound to the soliton. The presence of the Majorana mode renders the quantum exchange statistics of two solitons non-abelian. In order to allow detection of soliton statistics, we propose an interferometer geometry. The presence of Majorana modes is reflected in the interference pattern of the soliton beam.

• E. Grosfeld and A. Stern, PNAS 108, 11810 (2011), https://doi.org/10.1073/pnas.1101469108
• E. Grosfeld, B. Seradjeh and S. Vishveshwara, Physical Review B 83, 104513 (2011), https://doi.org/10.1103/PhysRevB.83.104513