Quantum mechanical effects are not limited to the microscopic. However we find that as the mass of an object increases, the classical domain supersedes quantum mechanical effects. This phenomena conventionally explained by quantum decoherence theory can be understood to come about due to “leaking” of information to the environment about the position and momentum of the object. Thus large objects lose quantum coherence faster than say microscopic objects. However, what happens when you completely isolate an object from its environment? Will the object continue to behave quantum mechanically? To realise this experimentally, one requires an object that can be prepared to behave quantum mechanically, but also one requires techniques to detect its quantum behaviour without destroying the quantum mechanical state.

Here at Southampton we have developed a novel setup whereby using 1550 nm laser light we are able to trap and isolate 100 nm particles in ultra-high vacuum. This new and thriving field is known as Levitated Optomechanics. Already, we have demonstrated the ability to control the centre-of-mass motion of the particle, by cooling its motion by a factor of a million. That is 150 phonons away from ground state.
This project, thus aims to further this work to reach the quantum ground state of the motional states of a levitated mechanical oscillator. The student will utilise and further develop continuous weak measurement and quantum feedback protocols. Implement experimental techniques for quantum state tomography. Using such a state the student will explore the quantum to classical transition for massive objects. Thereby addressing foundational question in quantum mechanics: namely, can one realise macroscopic quantum mechanical states of matter?

We are looking for highly motivated and hands-on candidates with an interest to set up and work with sophisticated experiments. Good knowledge and understanding of optics and quantum mechanics is required. A working knowledge and hands on experience of quantum optics is desirable. Experience of any of the following would be advantageous: feedback stabilization with FPGA digital electronics, work with Ultra-high vacuum systems, fibre and diode lasers. As well as, programming in Matlab, Python and Labview for data analysis and data-acquisition.

[For more information, please visit our group website at http://phyweb.phys.soton.ac.uk/matterwave/html/  and contact prof. Hendrik Ulbricht (h.ulbricht@soton.ac.uk).