Research Fellow in Experimental Quantum Optics with Levitated Particles

Full Time Fixed Term until 31/05/2025

Closing Date: Thursday 13 April 2023

Interview Date: To be confirmed

You will join the research group of Professor Hendrik Ulbricht (www.quantumnano.org) at the School of Physics and Astronomy at the University of Southampton on the EPSRC funded joint project 'NoHarmMacro' with our theory collaborator Professor Sougato Bose, Department of Physics and Astronomy at University College London. 

The overarching goal of this project is to perform a levitated optomechanical experiment that, by sampling the Leggett-Garg inequality (LGI) for a coherent motional state of a nanoparticle, directly probing quantum non-locality in the context of predictions made by macroscopic realism. 

Can the most "classical-like" of all quantum states, namely the Schrödinger coherent state of a harmonic oscillator, exhibit nonclassical behavior? We find that for an oscillating object initially in a coherent state, merely by observing at various instants which spatial region the object is in, the Leggett-Garg inequality (LGI) can be violated through a genuine negative result measurement, thereby repudiating the everyday notion of macrorealism. This violation thus reveals an unnoticed nonclassicality of the very state which epitomizes classicality within the quantum description. It is found that for any given mass and oscillator frequency, a significant quantum violation of LGI can be obtained by suitably choosing the initial peak momentum of the coherent state wave packet. It thus opens up potentially the simplest way (without coupling with any ancillary quantum system or using nonlinearity) for testing whether various recently engineered and sought after macroscopic oscillators, such as feedback cooled thermal trapped nanoparticles, are indeed bona fide nonclassical objects.

In order to reach this goal, we will develop an experimental platform that will allow the following achievements: 1) To rapidly repeat single-particle experimental dynamical trajectories to gain sufficient counting statistics in order to reconstruct the unique features of the delocalized quantum state; 2) To trap and manipulate (cool) sufficiently large particles (around 100 nm in diameter), to enable sufficient time for the wavefunction evolution, and to realise position measurements at sufficient high resolution - which is the challenging part of NoHarmMacro. The NoHarmMacro experiment will open the door to a new macroscopic domain for testing quantum mechanics in the low energy non-relativistic regime -- the very regime where gravity is expected to affect the dynamics of quantum systems.

To be successful you will have a PhD* or equivalent professional qualifications and experience in experimental quantum physics or electronics or related topic. You should have expertise in at least one of the following experimental research fields: levitated mechanics or microwave optomechanics or experimental quantum optics.

Applications for Research Fellow positions will be considered from candidates who are working towards or nearing completion of a relevant PhD qualification.

The post is available with a start date as soon as possible, and ideally by June 2023, and is initially for two years due to funding restrictions with a possibility of an extension.

Equality, Diversity & Inclusion is central to the ethos in Physics & Astronomy. We are strongly committed to diversity in both the academic & student population, and in recognition we received the renewal of an Athena SWAN Silver award in 2023 & the Institute of Physics Project Juno Champion status in 2019. Physics and Astronomy gives full consideration to applicants that wish to work flexibly, including part-time, & due consideration will be given to applicants who have taken a career break. Please visit https://www.phys.soton.ac.uk/EqualityandDiversity

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