Are you a highly-motivated student with excellent laboratory skills for performing state-of-the-art quantum physics experiments on four of our projects?
The strontium quantum gases group is headed by Prof. Florian Schreck and is part of the Quantum Gases and Quantum Information (QG&QI) cluster at the University of Amsterdam (Institute of Physics). The main focus of the group is the exploitation of Sr quantum gases for novel precision measurement techniques and the study of many-body physics. We have three open PhD positions within our Innovative Training Network MoSaiQC, which in this context are called early stage researchers (ESRs).
You will participate in network meetings across Europe, where you will learn about quantum technology from experts in the field and train essential skills, such as academic writing and outreach. You will participate in a summer school on clocks and organize a conference together with the other ESRs. You will spend half a year in the lab of a partner in either Copenhagen, Torun or Birmingham. You will participate in outreach events. During the public days of University of Amsterdam (UvA), you can present your experiment in talks and labtours or present physics demonstration experiments that you have developed and built. You are encouraged to join teams at UvA that prepare special events for minority groups, which encompass for example guiding pupils to create holograms.
The ESRs shall at the date of recruitment be in the first four years (full-time equivalent research experience) of their research careers and have not been awarded a doctoral degree. They must not have resided or carried out their main activity (e.g. work, studies) in the Netherlands for more than 12 months in the three years immediately prior the recruitment date. Please take a look at the other open PhD positions on the UvA’s website if you do not fulfil these eligibility criteria.
What are you going to do?
ESR1 – Compact atomic sources and beams for steady-state superradiant lasers
Steady-state atomic beam sources are crucial to realizing superradiant clocks and beneficial for quantum sensing with ultracold atoms in general. We have developed a continuous beam of ultracold atoms of unprecedented brightness and phase-space density and can create steady-state Bose-Einstein condensates. This continuous source of atoms is one of the foundations of our attempts to develop continuous superradiant clocks within iqClock.
The source we have developed so far is rather large and needs to be shrunk in size and complexity to enable more researchers to use them and to bring them out of the lab into the field. We are developing new concepts for generating ultra-cold strontium beams based on compact ovens, 2D MOTs, Grating MOTs and desorption cells. The starting point of ESR1’s project will be to develop and compare a range of different technology approaches and to build and characterize the best approach. The ESR will then use the knowledge gained to advance our attempts to build continuous superradiant lasers and possibly even an atom laser. Another aspect of ESR1’s work will be to develop advanced laser sources.
ESR2 – Precision laser stabilization and locking
The core of ESR2’s project is to develop an ultrastable laser and use it for research. ERS2 will build an ultrastable, high-finesse cavity and lock a laser to it such that it has a linewidth well below 1 Hz. Light will be sent from this laser through phase-stabilized fiber links to the superradiant clock we develop within iqClock and serve to characterize its precision.
These characterizations will be used to identify precision limiting effects and to improve the clock. A further research opportunity is to use this laser for internal state control in our programmable quantum simulator. Another aspect of ESR2’s work will be the development of a scalable and simple system to lock all lasers required to operate a superradiant clock.
ESR3 – High finesse cavities for strong atom-light interaction
High-finesse cavities loaded with ultra-cold atoms are a key to future applications harnessing strong atom-light interactions. These include superradiant optical clocks, sensors, quantum memories, quantum simulation and quantum information processing.
As part of our goal of making a steady-state superradiant optical clock we are developing high finesse UHV vacuum cavities that can be loaded with ultracold strontium atoms. For steady-state operation we need to continuously and efficiently load atoms from the ultra-cold strontium beam developed by ESR1 into the cavity. Furthermore the atoms in the cavity need to be held tightly by a magic wavelength lattice, which doesn’t shift the Sr clock frequency. ESR3 will work closely with the iqClock team on all these topics.
These ESR positions will be embedded within two projects.
Project 1: Continuous atom laser
In this project we try to build the first continuous atom laser. An atom laser is a beam of atoms that is described by a coherent matter wave. So far only short atom laser pulses have been created by outcoupling a beam of atoms from a Bose-Einstein condensate (BEC). The laser stops working when all atoms of the BEC have been outcoupled, requiring the creation of a new BEC for the next atom laser pulse.
BEC creation is usually a lengthy process, requiring several cooling stages to be executed one after the other in time. We have built a machine that can execute these stages one after the other in space [1, 2], reaching a steady-state Bose-Einstein condensate. We will now study the properties of this driven-dissipative BEC and then develop the machine further to produce atom laser beams, and explore and exploit their properties. Insights that we gain to produce the atom laser will also advance project 2.
Project 2: Superradiant Sr clock
In this project we develop a new type of optical clock: a continuously operating superradiant clock. Optical clocks exploit mHz linewidth transitions of atoms as frequency references and can achieve an accuracy that corresponds to going one second wrong over the lifetime of the universe. Conventional clocks operate by stabilizing a laser on the atomic clock transition and reading out the laser frequency by using an optical frequency comb. The interrogated atoms have to be extremely cold in order for the Doppler effect not to distort the measurement. Preparing a sample of atoms at ultracold temperatures takes time. To bridge that time the clock laser is short-term stabilized on a cavity.
Here we want to improve and simplify the clock by creating a laser from direct emission of light on the clock transition. Since the transition is so narrow an atom will spontaneously emit a photon only every minute or so, which doesn’t give us enough photons to do anything with. To enhance emission we use superradiance. By making it impossible to know which atom in an ensemble emitted a photon, the ensemble will enter a superposition state that is more likely to emit another photon, creating an avalanche effect and usually resulting in a ‘superradiant’ flash of light . The main challenge of this project is to prolong this flash to eternity by feeding new atoms into the superradiantly lasing ensemble.
This is challenging since the light used to laser cool the atoms from room temperature to the microKelvin regime decohers the superradiantly lasing ensemble. This challenge can be solved using a new technique that we have developed over the last years within project 1 [1, 2]. We are able to create Sr atomic beams with unprecedented brilliance and steady-state Sr samples close to quantum degeneracy. Crucially, this beam of ultracold Sr atoms is available in a region with very little laser cooling straylight, an important ingredient in feeding a superradiantly lasing ensemble forever.
This project has three parts. In one part we will create a superradiant laser on a kHz-wide transition, collaborating with the group of Jan Thomsen in Copenhagen. In the second part we’ll attempt to build a superradiant clock on a mHz-wide transition of Sr together with the group of Michał Zawada in Torun. The third part will be the exploration of the foundations of superradiant lasing in Amsterdam. Our ideas for this part range from the study of many-body effects in driven-interacting systems, over cavity coupled spin-lattice models, to cavity-cooling of a stream of atoms to quantum degeneracy, forming a continuous atom laser.
- Chun-Chia Chen (陳俊嘉), Shayne Bennetts, Rodrigo González Escudero, Benjamin Pasquiou, Florian Schreck, Continuous guided strontium beam with high phase-space density, arXiv:1907.02793 (2019).
- Shayne Bennetts, Chun-Chia Chen (陳俊嘉), Benjamin Pasquiou, and Florian Schreck, Steady-State Magneto-Optical Trap with 100-Fold Improved Phase-Space Density, Phys. Rev. Lett. 119, 223202 (2017).
- Matthew A. Norcia, Matthew N. Winchester, Julia R. K. Cline and James K. Thompson, Superradiance on the millihertz linewidth strontium clock transition, Science Advances 2, e1601231 (2016).
What do we require?
You hold an MSc. or equivalent in physics or a related field and are requested to motivate why you apply for the position and to supply a CV.
Other skills/experiences/documents that would benefit your application are:
- previous experience in an optical, atomic or molecular physics lab;
- working knowledge of a programming language (matlab, C++ or equivalent);
- excellent English oral and written communication skills;
- scientific publications.
To foster diversity in our research group, we will especially appreciate applications from excellent female candidates.
A temporary contract for 38 hours per week for the duration of 4 years (initial appointment will be for a period of 18 months and after satisfactory evaluation it will be extended for a total duration of 4 years) and should lead to a dissertation (PhD thesis). We will draft an educational plan that includes attendance of courses and (international) meetings. We also expect you to assist in teaching undergraduates and master students.
The salary, depending on relevant experience before the beginning of the employment contract, will be €2,325 to €2,972 (scale P) gross per month, based on a full-time contract (38 hours a week), exclusive 8 % holiday allowance and 8.3 % end-of-year bonus. A favourable tax agreement, the ‘30% ruling’, may apply to non-Dutch applicants. The Collective Labour Agreement of Dutch Universities is applicable.
Are you curious about our extensive package of secondary employment benefits like our excellent opportunities for study and development? Then find out more about working at the Faculty of Science.
About the Faculty of Science and the IoP
The Faculty of Science has a student body of around 7,000, as well as 1,600 members of staff working in education, research or support services. Researchers and students at the Faculty of Science are fascinated by every aspect of how the world works, be it elementary particles, the birth of the universe or the functioning of the brain.
The Institute of Physics is situated in new, purpose-built laboratories and teaching space in the building of the Faculty of Science in the Science Park Amsterdam. This location also plays host to numerous national research institutes such as AMOLF (nanophotonics, biomolecular systems, photovoltaics), NIKHEF (Subatomic Physics) and CWI (mathematics and Computer Science), as well as ARCNL (Advanced Research Center for Nanolithography, which combines the leading Dutch tech firm ASML with both Amsterdam universities and AMOLF).
Do you have questions about this vacancy? Or do you want to know more about our organisation? Please contact:
The UvA is an equal-opportunity employer. We prioritise diversity and are committed to creating an inclusive environment for everyone. We value a spirit of enquiry and perseverance, provide the space to keep asking questions, and promote a culture of curiosity and creativity.
Do you recognize yourself in the job profile? Then we look forward to receiving your application.
You may apply using the link below. Your application must include:
- a curriculum vitae;
- a motivation letter that explains why you have chosen to apply for this specific position with a statement of your research experience and interests and how these relate to this project;
- title and summary of your Master thesis.
Please make sure all your material is attached in only one pdf. The single pdf can be uploaded in the field marked CV in the application form. To accelerate the review of your application, please also send it to Florian Schreck per email.
The UvA is the party responsible for processing your personal data (the ‘controller’) within the meaning of the General Data Protection Regulation (‘GDPR’). To know how we process your personal data please click here.
We will consider applications as they are received with flexible starting dates, and the positions will remain open until five suitable candidates have been identified.
The formal closing date is 31 July 2020. The selection procedure includes three interview rounds and a reference check. The first two interviews will be done by video calls and the third in person and include presentations of your master thesis and an interview on experimental quantum physics and an experimental challenge. Because of COVID-19 it may be that the last round has to be done by video call, in which case the experimental challenge will be replaced by a quiz on a research literature assignment. Please read the Charter and Code for recruitment here. #LI-DNP