Summer Research Fellowship Programme of India's Science Academies

Quantum Information: Implementation of quantum heat engine using spin-bus model

Rohit Patil

IISER Pune, Maharashtra, 411008

Dr Asoka Biswas

IIT Ropar, Punjab, 140001


My primary motivation for studying this topic is to get an overview of the field of quantum thermodynamics focusing mainly on the quantum information aspect; also to explore quantum heat engine with spin bus architecture as its working substance. This topic broadly involves three areas of physics namely, quantum thermodynamics, quantum information theory and the theory of spin chains. Quantum information theory is linked with thermodynamics, exemplified by Landauer’s principle. The quantum mutual information or quantum correlations can act as a fuel for running quantum heat engine, which is aptly quantified via a measure called discord. Quantum discord is an integral resource apart from entanglement. Lastly, a spin-bus is a chain of 'n' spins with Heisenberg Hamiltonian, which when coupled with a few external qubits, acts as a medium for quantum computation such as the creation of multipartite entanglement. The spin-bus can be reduced to an effective two-level system which is due to significant energy gap between the ground state mode and the excited states. I have tried to reproduce the result for the energy gap numerically along with a few problems solved using QuTiP. I further hope to understand this system via the effective Hamiltonian approach which would be useful for analysing the spin-bus model.

Keywords: Quantum discord, Quantum thermodynamics, Heisenberg spin-chain, Multipartite entanglement

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