Scientific Internship: Brownian ratchets with nanomechanical resonators

Date posted November 11, 2021
Type Scientific Internships

Heat arises from the random agitation of atoms and molecules. Because thermal agitation is random, it is very difficult to extract useful work from it: If we connect an object (for example, a weight) to a particle experiencing thermal agitation, half of the time it will get pushed in the direction we want, but the other half it will get pushed in the opposite direction – leaving us at essentially the same spot. Since the beginnings of the kinetic theory of heat, people have speculated with the possibility of rectifying thermal agitation. This involves designing some type of ‘clever coupling’ that facilitates motion in one direction but not the other – for example with mechanisms like the one that prevents us from pedaling backwards on a bicycle.  This speculation has led to a variety of hypothetical machines, including the Maxwell demon, the Feynman ratchet and the Szilard engine. 

We now know that, due to the laws of thermodynamics, it is not possible for those devices to extract energy by cooling down a single heat reservoir. This precludes us from building those hypothetical machines as originally conceived. However, it is still possible to rectify random vibrations as long as our machine is connected to two different temperatures. Such a machine is referred to as a ‘stochastic heat engine’. Building a stochastic heat engine is extremely challenging because the amount of thermal energy contained in each particle is very small. Therefore, the engine must be microscopic, delicately optimized and have low power losses.

In this internship, you will design and build a stochastic heat engine consisting of microscopic vibrating strings. You will carefully design the shapes and vibration frequencies of the strings so they rectify thermal agitation. The design will be done using finite element software (ANSYS) and stochastic simulations using our existing codes written in C++. The engine will be fabricated using nanolithography and two-photon polymerization – a type of 3D printing that operates at the nanoscale. You will then measure the vibrations in vacuum using laser vibrometry.

About the group

The hypersmart matter group investigates the processing of information by structured elastic materials. We combine an applied drive to answer the low-energy and ubiquitous computing needs of the future, with a fundamental interest to understand the limits and principles that govern information processing in physical systems. To achieve these goals, we combine advances in simulation and modelling with cleanroom fabrication techniques.


The internship is open to Master’s degree candidates from a range of backgrounds, including Engineering, Physics, Computer Science, Mathematics or a related field. We are looking for ambitious candidates who are excited about building something that has never been done before. Specific experience with programming languages, software or equipment is not mandatory, but motivation and desire to learn is.

The internship must be a mandatory part of your curriculum. You have a nationality of an EU member state and/or you are a student at a Netherlands University. Please note: As of January 2021 the UK is no longer an EU member state. You must be available for at least 6 months.

Terms of employment

At the start of the traineeship your trainee plan will be set out, in consultation with your AMOLF supervisor.

Contact info

Dr. Marc Serra Garcia
Group leader Hypersmart matter
Phone: +31 (0)20-754 7201

You can respond to this vacancy online via the button below.

Please annex your:
–  One-page motivation letter;
–  Resume;
–  List of followed courses plus grades.

Applications will be evaluated on a rolling basis and as soon as an excellent match is made, the position will be filled.

Online screening may be part of the selection.

Commercial activities in response to this ad are not appreciated.