This summer/fall we are going to hire two PhD students to work with us on new computational approaches to quantum transport. Candidates should have a strong background in theoretical physics (ideally condensed matter / quantum transport) as well as experience in software design and development.

Each PhD project will consist of three overlapping phases:
(1) Prototyping of a new computational approach for quantum transport problems.
(2) Implementation of the new approach within the framework of the Kwant code [1].
(3) Application of the newly gained capabilities to unsolved physical problems, in close collaboration with experts in the particular fields.

The two subjects are introduced in some detail at the bottom of this announcement.

The research will take place at the Institute for Nanoscience and Cryogenics (INAC) of CEA Grenoble (France) over the course of three years under the supervision of Christoph Groth and Xavier Waintal in close collaboration with Michael Wimmer and Anton Akhmerov of Delft University of Technology (Netherlands).

The city of Grenoble offers a superb combination of a rich international scientific environment with a unique natural and cultural setting. Grenoble is home to a vibrant nanoscience research community [2], several international research institutions (ESRF synchrotron, ILL neutron source, and others) and 60,000 university students. The city is literally surrounded by the French alps that offer numerous possibilities for outdoor activities.

Interested candidates are invited to send an application to Christoph Groth [3] with the subject “PhD application Kwant 2015”. Applications should include

• a CV,
• Email addresses of persons that can be asked for a recommendation,
• an example of theoretical physical work done by the applicant (e.g. a project, or a master thesis).

Applicants are invited to also provide the source code of a program that highlights their software engineering experience.

[1] http://kwant-project.org/
[2] http://www.fondation-nanosciences.fr/RTRA/en/14/vo...
[3] mailto:[email protected]

Subject 1: Scalable electrostatics computations

Both single-particle simulations of quantum nanoelectronics and pure electrostatics simulations are a standard problem. However, in order to accurately simulate complex quantum systems, one needs to combine both approaches. This transforms the linear electrostatic problem into a non-linear integro-differential system of equations with rapidly growing complexity. Current approaches at exactly solving the combined problem are limited to small systems of around 10 nanometers in linear size. Advancing the state of the art is becoming increasingly important to improve our understanding of modern experiments (e.g. spin qubits, mesoscale transport).

Subject 2: Multidimensional scattering

Traditionally, quantum transport codes have focused on the 1-d
scattering problem: a finite scattering region with attached semi-infinite quasi-1-d electrodes. While this suffices to calculate the basic experimental observables (for example conductance), solving the more general n-dimensional case would allow to

• characterize disordered materials with a non-spherical band structure,
• calculate transport properties of crystallographic defects,
• treat hybrid systems with different dimensionalities (e.g. a 1-d nanowire coupled to a 3-d superconductor).

The first two capabilities would greatly aid in the analysis of realistic systems and materials that in practice contain disorder, dislocations and impurities. The last capability would be highly valuable for example for studies of Majorana fermions.