Lund University, Faculty of Engineering, LTH, Department of Physics

Lund University was founded in 1666 and is repeatedly ranked among the world’s top 100 universities. The University has 40 000 students and 7 400 staff based in Lund, Helsingborg and Malmö. We are united in our efforts to understand, explain and improve our world and the human condition.

LTH forms the Faculty of Engineering at Lund University, with approximately 9 000 students. The research carried out at LTH is of a high international standard and we are continuously developing our teaching methods and adapting our courses to current needs.

The Department of Physics is with a staff of about 350 scientists and educators one of the largest departments within Lund University. There are seven research divisions and a number of research centra within the department. The research activities at the department cover a broad spectrum of modern physics. www.fysik.lu.se/english.

The Division of Atomic Physics at the Faculty of Engineering (LTH), Lund University, Sweden has a staff of over 50 researchers including graduate students. The research at the division is mainly focused on lasers and optics, and particular topics ranges from spectroscopy, high intensity light matter interaction, to quantum information and bio-photonics. More information can be found at http://www.atomic.physics.lu.se/.

The presently announced position(s) will be directly linked to the quantum information group, which has a strong activity on quantum information and quantum optics using rare-earth-ion-doped crystals, as well as harnessing slow light effects for various applications. The group has recently attracted important grants in these areas, including from the Wallenberg foundation and the recently initiated EU Flagship on quantum technologies, which forms the basis for the 1-2 new PhD positions within the group.

As a country, Sweden offers one of the best employment conditions in the world for Ph.D. students, including an actual yearly salary of about €34000 and a strong social security net. 

Job assignment and topic description
The primary job assignment as a Ph.D. student is research related to either of the two topics that we describe below. The applicants are encouraged to describe their relative interest in the two topics in their cover letter. The final choice of topic will then be decided in discussion with the successful applicant(s).

Area 1: Experimental quantum information with rare-earth ions

Quantum technology with rare-earth ions in solids is a fast growing field that has been recognized in the EU Flagship as the only contender to the two main approaches of quantum computing (superconducting qubits and ion traps). Rare-earth-ion doped crystals are unique among solid state systems because of their millisecond optical coherence times, combined with spin coherence times of more than 6 hours. There is also a strong and controllable dipole-dipole interaction between ions, which are close to each other in space and this interaction can provide reliable quantum gate operations. The main benefits are good interconnectivity of the qubits and a potentially very high qubit density. However, at present only a single full qubit has been realized, which means that the coming few years will be very impactful in demonstrating the potential of the rare-earth approach, and we are now looking for a Ph.D. student to join is in this exciting near future.

The primary challenge right now is developing detection and interactions with single ions inside the crystals. We are pursuing several approaches for this, including coupling different qubit and readout ion species and also enhancement using micro cavity QED effects. Once this has been established, the strong dipole-dipole interactions between the ions can be used to extend the work to the multi-qubit regime, and to explore the high qubit scaling potential. 

Area 2: Applications of unique slow and fast light materials

Under some special circumstances, the speed of light can be slowed down dramatically. In rare-earth-ion doped crystals, the crystal acts as a natural trap for the rare-earth dopant ions. These crystals offer a unique solid state system, where light can be slowed down more than a factor 100 000, without any artificial trap or strong simultaneous pumping light beams. In this project potential applications of these slow light materials will be explored. One of the main ideas which will be investigated is the potential of slow light cavities to improve the stability of lasers beyond what is currently possible. The frequency stability of lasers locked to reference cavities is presently limited by the thermal Brownian motion of the atoms constituting the reference cavities, which causes the length of the cavity to fluctuate with time. The current limit for the average cavity length variation is ~0.1 proton radius. We have recently demonstrated that slow light effects in Fabry-Pérot cavities made of rare-earth-ion-doped crystal materials can decrease cavity mode spacing and line widths by 3-5 orders of magnitude. Furthermore, we have shown that in such cavities the effect of length fluctuations on the cavity resonance frequency is decreased by 3-5 orders of magnitude compared to a conventional vacuum cavity of the same length. The aim here is to explore the possibility to use this type of cavities for improving laser frequency stabilization beyond the current limits. At the other end of our control of the speed of light, we would also like to investigate the possibility to use fast light (pulses travelling faster than c), to increase the sensitivity for certain applications, e.g. gravity wave detection.

Entry requirements
A formal requirement for being accepted to doctoral studies in physics is:

  • a university degree on advanced level within a related field, such as a Master's degree in physics or equivalent, or
  • substantial advanced course work at the Master level, or comparable, including an independent research project
A person meets the specific admission requirements for third cycle studies in physics if he or she has:
  • at least 30 credits of relevance to the subject, including at least 15 second-cycle credits, and a second-cycle degree project of at least 15 credits of relevance to the field, or
  • a second cycle degree in a relevant field.
Furthermore, the acceptance is based on the estimated ability to accomplish postgraduate studies.

Other requirements:

Good ability in spoken and written English is a requirement.

Basis of assessment
Selection to doctoral studies is based on the expected ability to perform well in the studies. The evaluation of the ability to perform well is based primarily on the results of studies at the basic and advanced levels, in particular:

  1. Knowledge and skills relevant to doctoral studies within the research area, such as a broad and thorough experience in e.g. physics, optics, spectroscopy and lasers.
  2. Estimated ability to work independently and the ability to formulate and solve scientific questions. This ability can be established, for example, based on undergraduate research experiences, a Master's thesis or in a discussion of scientific problems during a possible interview.
  3. Skills in written and oral communication.
  4. Other experience relevant to doctoral studies, such as professional experience.
  5. Good ability for cooperation, drive, creativity and to structure your work is considered as positive personal attributes.
  6. Previous experience of working in optical laboratories
  7. Skills in programming (MATLAB, Labview, etc.)
  8. Answer to the assessment question below
Assessment question:

Light with a vacuum wavelength of 589 nm is entering an acrylic glass plate (PMMA type). What is the frequency and wavelength of the light inside the acrylic glass plate?
– Write your answers in the cover letter, together with a brief explanation. 

Terms of employment
A PhD position is an employment with the main duty to be engaged in PhD studies according to the study plan. The duration of PhD studies is 4 years full time studies. In addition, those appointed to doctoral student position may be required to work with educational tasks, research and technical/administrative duties at a level of at most 20% of full time. The position is then extended correspondingly, however not longer than corresponding to 5 years full time employment. PhD positions are subject to special regulations. These can be found in the Swedish Higher Education Ordinance (1993:100), chapter 5, 1-7 §§. Only those admitted to PhD-studies may be appointed to a PhD position. 

Application procedure
Apply online. Applications must contain a cover letter in which applicants describe themselves and their particular research interests and in particular in a non-generic way explains why they are interested in the present position. Applications must also include a CV, a copy of the applicant’s Master’s thesis (or a summary text if the thesis is not yet completed), contact details of at least two references, copies of grade certificates, and any other documents that the applicant wishes to refer to. In addition, the cover letter should address the assessment question described above in the section Basis of assessment.

Type of employment Temporary position longer than 6 months
First day of employment as soon as possible
Salary Monthly salary
Number of positions 1
Working hours 100
City Lund
County Skåne län
Country Sweden
Reference number PA2018/3773
Contact
  • Andreas Walther, +46 46 222 9625, andreas.walther@fysik.lth.se
Union representative
  • OFR/ST:Fackförbundet ST:s kansli, 046-222 93 62
  • SACO:Saco-s-rådet vid Lunds universitet, 046-222 93 64
Published 09.Jan.2019
Last application date 06.Feb.2019 11:59 PM CET

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