You are invited to attend the virtual Long Range Collequium organised by the Virtual Science Forum. This is a bi-weekly colloquium focussing on condensed matter in physics and quantum information. The first three speakers are Liang Fu (MIT), Charles Marcus (University of Copenhagen and Microsoft Research, and Vidya Mahavan (University of Illinois).

The upcoming talk by Liang Fu on "Charge Transfer Excitations, Pair Density Waves, and Superconductivity in Moiré Materials" It is going to take place Wednesday 15 April at 19:30. If you want to attend, please register (the attendance is open to everyone and free).

About us: we are a group of volunteer physicists developing a virtual conference initiative, the Virtual Science Forum (VSF). All of our events are open to the public and free.

Anton Akhmerov,
On behalf of the VSF organizers

Outline colloquium:

"Charge Transfer Excitations, Pair Density Waves, and Superconductivity in Moiré Materials"

Transition metal dichalcogenide heterobilayers are a new class of tunable Moiré systems attracting interest as quantum simulators of strongly-interacting electrons in two dimensions. In this talk, I will argue that the correlated insulator recently observed in WSe2/WS2 at half filling is a charge-transfer insulator similar to cuprates, in which hole doping induces a charge from anion-like to cation-like orbitals at different locations in the Moiré unit cell [1]. Interestingly, at small doping, tightly-bound charge-2e "trimers" consisting of two holes bound to a charge-transfer exciton can form to lower the total electrostatic repulsion [2]. When the bandwidth of doped holes is small, trimers crystallize into insulating pair density waves at a sequence of commensurate doping levels. When the bandwidth becomes comparable to the pair binding energy, itinerant holes and charge-2e trimers interact resonantly, leading to unconventional superconductivity similar to superfluidity in an ultracold Fermi gas near Feshbach resonance.