ITAMP Lunch Seminar
Speaker: Michal Tomza, (Warsaw University)
Date: Thursday, November 16th
Time: 12:00-1:00 pm
Includes Pizza.
Title: Quantum-chemical approach to few-body quantum systems
Abstract: In the first part I will present the application of the
quantum-chemical coupled-cluster method to study the properties of a
balanced two-component Fermi gas in a one-dimensional harmonic trap.
For few fermions we recover the results of exact diagonalization, yet
with this method we are able to study much larger systems. We compute
the energy, the chemical potential, the pairing gap, and the density
profile of the trapped clouds, smoothly mapping the crossover between
the few-body and many-body limits. The energy is found to converge
surprisingly rapidly to the many-body result for every value of the
interaction strength. Many more particles are instead needed to give
rise to the nonanalytic behavior of the pairing gap, and to smoothen
the pronounced even-odd oscillations of the chemical potential induced
by the shell structure of the trap
In the second part I will present our investigations of two
interacting ultracold polar molecules described as distinguishable
quantum rigid rotors effectively trapped in a one-dimensional harmonic
potential.
The molecules interact via a multichannel two-body contact potential
incorporating the short-range anisotropy of intermolecular
interactions. The impact of external electric and magnetic fields
resulting in Stark and Zeeman shifts of molecular rovibrational states
is also included. The importance and interplay of the molecular
rotational structure, anisotropic interactions, spin-rotation
coupling, electric and magnetic fields, and harmonic trapping
potential are examined in detail and compared to the system of two
harmonically trapped distinguishable atoms. Presented model and
results may provide microscopic parameters for molecular many-body
Hamiltonians and may be useful for the development of bottom-up
molecule-by-molecule assembled molecular quantum simulators.
Location: B-106 @ Center for Astrophysics (60 Garden Street)
Directions: After entering the lobby of the CfA, turn right to enter the hallway of the B building. In the hallway, turn right again, B-106 will be at the end of the hallway on the left side.