Embedding allows to simulate large system sizes by partitioning the system of interest into an active space that needs computing at a high level of accuracy, surrounded by an effective bath of all remaining parts of the system. Quantum computers are expected to provide advantage in the evaluation of dynamical properties for such systems, which become intractable at moderate sizes even with the most efficient classical computing methods based on tensor networks [Jamet, Lindoy, et al., APL Quantum 2, 016121 (2025)]. However, one of main limitations of quantum computing algorithms for embedding is that the bath is always finite due to the finite number of qubits. The most advanced classical computing method to overcome such finite size limits in dynamics simulations adds specific dissipative terms to the bath orbitals to broaden the states and obtain the targeted active-space/bath interactions. In this project, you will develop methods to add such dissipative terms to the qubits representing the bath, thereby overcoming this finite-size problem in quantum algorithms. This will require developing optimized system representations and transformations onto qubits and quantum simulator systems, where you will tailor the dissipative terms to the targeted hardware platforms such as Rydberg atoms systems and superconducting qubits. This will allow you to inform hardware design proposing types of qubits and operation for active space and bath, such as different atomic species or control fields, which you will suggest to our experimental collaborators.  Within the project, a theoretical model to estimate the fundamental uncertainty of quantum algorithms will be established, and used to develop quantum software that minimises errors on existing quantum computers. The methods will be included in the quantum software compilers developed at CQC, and will provide theoretical guidance for the experimental qubit measurements at NPL.  

The National Physical Laboratory is located south-west of London and is a purpose-built research institute, located in beautiful surroundings on the edge of Bushy Park.  NPL is the UK’s National Measurement Institute providing high precision measurements and reference standards to academic research and industry. Its research sits at the intersection between scientific discovery and industrial application.

The University of Strathclyde, located in Glasgow city centre, is a multi-award-winning UK university and is home to over 22000 students from 100 countries.  For more than 200 years Strathclyde has been delivering academic excellence through world-class research and teaching, providing students with flexible, innovative learning in preparation for their chosen career path.  Strathclyde received a five-star rating in a QS audit of universities’ key performance areas.