Nanoscale thermodynamics: From Expeanriments and Applications to a practical Theory (noFEAT)

Thermodynamics plays a central role in science and engineering. Introduced at the beginning of the industrial revolution it has been applied ever since to design a great variety of useful large scale devices, from fridges to solar cells. Now technological progress is increasingly miniaturising to the nanoscale and into the quantum regime where thermal fluctuations compete with quantum fluctuations. Recent theoretical advances have started to fill the void of a thermodynamic theory that fully includes non-equilibrium aspects, small ensemble sizes and quantum properties. However, consolidating the newly developed tools and making them of practical use, by specifying implications for experiment and ultimately technology, remain challenges that need to be solved.

This project aims to bridge this gap in our understanding. To achieve this, the team will take a synergetic approach:

We will first clarify theoretically in what way quantum coherence can be regarded as a thermodynamic resource in quantum experiments where control is limited and noise is present. We will secondly use existing theoretical methods and develop new tools to analyse quantum thermodynamic experiments that attempt to show that one can draw work from quantum coherences.

Thirdly, we will set up a new theoretical framework that captures the thermodynamic properties of small scale quantum systems, which do not obey the standard thermodynamic assumption of the system interacting weakly with its environment. This includes deriving strong coupling corrections to the standard repertoire of equilibrium thermodynamics, such as the system's internal energy, its entropy and its heat capacity.

Finally, the theoretical description of nanoscale quantum systems will be translated into the context of magnetic hard disks. Hard disks store bits of information in nanometre-sized grains, which are made up of many individual quantum spins, and interact with their environment consisting of neighbouring grains as well as the crystal lattice of the magnetic material and electrons. The miniaturisation of magnetic disks is an obvious technological setting where the new theoretical methods can be applied and tested. The team will build a test model for hard disks that store information in spin-grains whose size is reduced below 8 nm. By including strong coupling and quantum effects we hope to improve simulations of the magnetisation dynamics of these small grains and identify which sources of damping and noise affect the information stored on these disks. This is important input for UK hard drive manufacturers, such as Seagate Technology which is a partner of this research programme, that helps them design hard drives that are cheap and reliable, allow for faster access times and have smaller drive sizes. The general public makes use of such hard disks for example when storing information on Dropbox, YouTube and using cloud services on smartphones.

The project combines interdisciplinary theoretical methods with advanced nanoscale experiments to extract fundamental physics insights that are then applied in an industrially relevant setting. With many technologies expected to push to the nanoscale in the next 10-20 years this is essential to enable us to harness finite size and quantum effects in modern technologies, with applications expected to range from small scale data storage and recording techniques to improvements in predictive use of medical data, imaging at small scales, energy capture and transfer in small machines, and manufacturing of nanoscale devices.

The project's long-term impact on industry lies in advancing our understanding of thermodynamic processes at the nanoscale. At these scales strong coupling and quantum effects become important and it is uncertain which parts of the established theoretical framework of thermodynamics are applicable and which have to be modified. The project's research will help remove this uncertainty and provide the necessary scientific basis for technological progress, with applications from computer chips to medicine that are set to address many socio-economic challenges of the coming 50 years.

In the medium-term the UK magnetic hard drive industry, such as Seagate, will benefit from the project. Seagate UK is a global leader producing 400 million recording heads per year, a quarter of the entire world's supply. This sophisticated manufacturing capability generates a surplus of more than £100 million per year to the UK economy. The hard drive industry seeks to increase the storage capacity of future hard drives while keeping their size small and their operation time fast. The project will provide a new quantum thermostat to model the equilibrium properties of a magnetic material and its magnetisation dynamics, and help predict optimal production parameters reducing the need to prepare and test samples. This will contribute to maintain an economically significant and highly sophisticated manufacturing capability in the UK, which provides more than 1500 jobs to highly skilled workers.

I have established contacts with representatives from Seagate (see letter of support) and academics working closely with Seagate (Roy Chantrell, see letter of support). To ensure the programme's findings can make full impact for industrial stakeholders I will visit Mark Gubbins and his R+D team at Seagate, update industry representatives who have expressed an interest in the proposed research, including Andrew Shields (Toshiba, see letter of support) and Colin Williams (D-Wave), and seek advice from the programme's Advisory Board which includes an industry expert, Ulrik Imberg (Huawei). I will organise a stakeholder workshop at the start of Year 3 bringing together a multidisciplinary range of scientists, industry experts and policy makers to discuss what scientific breakthroughs have recently been made and identify challenges of the UK industry that may be resolved with nanoscale thermodynamics expertise.

Nanoscale data storage devices that can quickly access large amounts of data will provide the storage capacity required for modern cloud storage services, such as Dropbox and smartphone data storage. Such devices are anticipated to allow improved large-scale data mining capabilities enabling, for example, the analysis of medical data that would feed into prevention, impacting directly on society's well-being. The long term impact of nanotechnologies on society is expected to include the improvement of healthcare through precision sensing, the provision of small scale and powerful computer chips, and efficient energy capture, such as photovoltaics.

Together with my team I will actively engage in raising the public's awareness and interest in quantum physics by contributing topical newspaper articles, giving stimulating public lectures, and explaining the scientific method and recent discoveries to the public at UK science festivals.

Finally, the project will train people in skills that are highly sought by UK academia and industry, including computer programming, team-working, public speaking, project and people management, and problem solving in general.