Karen Kheruntsyan

Quantum thermodynamics of ultracold atomic gases

The Second Quantum Revolution is currently underway, and represents the merging of thermodynamic concepts of heat and work, born during the Industrial Revolution, with quantum concepts of information processing and entanglement. But how do the classical ideas on the nature of heat and work translate to quantum devices? Do the laws of classical thermodynamics also dictate the behaviour of processes at a quantum level, or whether new laws are needed? The project intends to shed light on these fundamental questions by developing state-of-the-art computational models of quantum-scale machines and heat engines using the platform of ultracold atomic gases. Such gases represent arcehtypical examples of interacting many-body systems, however, characterising their equilibrium and nonequilibrium properties is a chellenging problem. The knowledge arising from the project is expected to underpin experimental breakthroughs in this emerging field and aid the development of new quantum technologies.

Stochastic quantum hydrodynamics: a new theoretical approach to nonequilibrium dynamics of quantum many-body systems

The project aims to develop theoretical tools to model and understand out-of-equilibrium behaviour of quantum fluids. Such fluids are formed in interacting many-particle systems at ultra-low temperatures, and understanding how these complex systems evolve dynamically when driven out of equilibrium remains a grand-challenge of modern quantum physics. The project intends to study the intriguing dynamical properties of quantum fluids formed by ultra-cold atomic gases, in particular, by atomic Bose and Fermi gases in one-dimensional (1D) waveguides. In such 1D waveguides, and more generally in systems of reduced dimensionality, the effects of quantum and thermal fluctuations are enhanced, compared to three-dimensional systems. As such, theoretical modelling of these systems confronts the challenges of quantum many-body physics heads on. Systems of reduced dimensionality are expected to play an increasingly important role in future quantum technologies, with its ever evolving trend in miniaturisation of electronic devices and precision measurement instruments. The expected outcomes of the project are the knowledge and theoretical tools required to underpin advances in quantum engineering applications, such as the design of quantum heat engines, the control of heat conduction in quantum nanowires and carbon nanotubes, and the fabrication of new energy-efficient materials. Specific sub-projects include:

• Development of new hydrodynamic theories of 1D quantum fluids at Euler and Navier-Stokes scales
• Whitlam modulation theory for propagation of 1D quantum shock waves
• Collective modes of 1D quantum fluids from the theory of Generalised Hydrodynamics (GHD)
• Quantum transport in 1D quantum fluids
• Quantum heat engines with ultra-cold atomic gases