Summer job as a project assistant in theoretical quantum science and technology

Description of the workplace
The division of mathematical physics spans both the faculties of natural science and engineering science (LTH), and it is a part of the department of physics. Research is conducted primarily in the fields of quantum many-body systems, which includes theoretical research in nuclear physics, nanometer physics, quantum information, atomic physics, and modeling of materials, with several collaborations internationally and within Lund University. Read more about the division here.

Work duties
The work duties will be to perform research within the field of quantum technology, with the focus of the work determined by the specific project topic.

There are five possible projects available, described briefly below. Four out of five summer work positions are financed by the Marianne and Marcus Wallenberg foundation through EDU-WACQT, an initiative for strengthening Swedish undergraduate education in Quantum Technology:

1. Sequential violations of Bell inequalities. Contact person: Armin Tavakoli.

Nonlocality is a fundamental phenomenon in quantum mechanics. It is considered to be the strongest known proof of non-classicality in physics. This phenomenon is closely tied to the possibility of violating Bell inequalities. In recent years there has been much interest in understanding how Bell inequalities can be violated multiple times using only a single quantum state, i.e. the non-locality can be ‘recycled’ repeatingly.

The purposes of this project is to explore the repeated violations of Bell inequalities. In particular, focus is on studying and characterising this via the most elementary quantum operations. Until recently, these operations were not believed to have the capability to violate Bell inequalities more than once. A successful result would pave the way for more far-reaching research on the topic.

2. The most non-projective quantum measurement. Contact person: Armin Tavakoli.

Traditional measurements in quantum mechanics are projections but the modern interpretation of the theory permits a more general formalism for measurements. These are called non-projective measurements. There are many known examples of such measurements but it remains unclear which of these are the ‘most non-projective’, i.e. which measurements that are absolutely the hardest to simulate when using only the traditional projective measurements.

The purpose of this project is to numerically study this question for the simplest quantum system (a qubit). A successful result would pave the way for more systematic studies of this research question, including the development of analytical simulation methods and studies of more complicated quantum systems?

3, 4 Information lattice for metal-insulator transitions. Contact person: Erik van Loon.

The information lattice is a way of characterizing at which length scales (quantum) information is contained in quantum many-body systems, based on the density matrix and von Neumann entropy of the system. This approach has been applied successfully to spin models and the Kitaev chain. In this project, the idea is to apply this approach to metal-insulator transitions, one of the hallmarks of quantum materials. This should be especially interesting since the electronic states of metals and insulators are completely different, going from momentum eigenstates to localized electrons, and this is expected to have dramatic consequences on the information lattice.

5. Quantum measurement and control of few-level systems. Contact person: Peter Samuelsson,

To measure and control individual quantum systems is of key importance for quantum technology applications and requires knowledge about the fundamental properties of quantum systems under measurement and feedback control. As a rule, the quantum systems are simultaneously coupled to an environment, inducing relaxation and dephasing to the quantum system during operation.

The purpose of this project is to investigate the effect of measurement and feedback on few-level quantum systems, single or coupled qubits or harmonic oscillators, weakly coupled to an environment. The investigations will be performed analytically in limiting parameter regimes and numerically in the more general case.

Qualifications

• Ongoing Swedish university education in physics or another subject relevant for the project, at bachelor, master or equivalent level.
• Very good knowledge of English, both spoken and written, is a requirement.

Other merits:

• Knowledge about the specific topic of the internship project applied for is considered a merit.
• Consideration will be given to good collaborative skills, drive and independence.

Terms of employment
This is a fixed term employment for 1,25 months on 100%. The working hours could also be 2.5 months on 50 %. Starting date and scope is decided in agreement with the project contact person.

Instructions on how to apply
Applications should include a cover letter stating the reasons why you are interested in the position and in what way the employment corresponds to your qualifications. Please specify which of the projects you apply for, and if more than one, provide an order of priority. The application should also contain a CV, degree certificate or equivalent, and other documents you wish to be considered (grade transcripts, contact information for your references, letters of recommendation, etc.).

Welcome with your application!