Witlef Wieczorek

Wallenberg Academy Fellow 2019

Natural Sciences

Dr Witlef Wieczorek

Chalmers University of Technology

Can Schrödinger’s cat weigh ten million times as much? 

In the peculiar world of quantum physics, a particle can be in two places at once. This is called quantum superposition. Wallenberg Academy Fellow Witlef Wieczorek will now investigate whether it is possible to superpose an object that is ten million times heavier than the current record. 

In 1935, the physicist Erwin Schrödinger devised a thought experiment based on the laws of quantum physics, in which a cat could be both dead and alive at the same time. The experiment was based on the nanoworld, where it is entirely normal for an object to be in two states simultaneously, although imagining that cats could be superposed goes against our intuition. 

However, in theory, quantum physics also applies to larger objects. Thus far, researchers have successfully observed superposition in atoms and larger molecules. The current record is a molecule that weighs 105 atomic mass units, which is the same as one hundred thousand hydrogen atoms. 

Dr Witlef Wieczorek from Chalmers University of Technology will now attempt to demonstrate superposition in an object that is ten million times heavier than the current record. He will conduct the experiment in a vacuum at low temperature and keep the object floating using a magnetic field created by a superconducting circuit. Due to things called superconducting quantum-interference devices and superconducting quantum bits, he is able to monitor and govern the movement of the floating object and create a superposition state. 

Foto: Marcus Marcetic