Noiseles holonomic quantum computation with higher-j physical spin

Sammanfattning

Quantum information and quantum computation is an area of quantum mechanics which utilizes quantum properties of particles in schemes for computation. These quantum schemes have been shown to improve computational capabilities for some systems. In quantum computation, the decoherence problem is a limiting factor. Decoherence is the process of loss of quantum information due to interaction from the environment, which puts a limit to how long a quantum computation is valid. There are ways to limit the effect of decoherence. The idea of a noiseless subsystem is to encode the quantum information in a smaller subsystem of the physical system that is not affected by decoherence. Holonomic quantum computation encodes quantum information in holonomies, making it more robust and less affected by decoherence. In this report, these two concepts are combined by encoding one logical qubit in three physical spin-1 particles. The approach to combine these concepts is entirely analytical. A Hamiltonian acting on the physical system is derived. To achieve a result which is possible to implement experimentally, the analytical derivation utilizes permutation operators to derive the Hamiltonian, which is known to be implementable experimentally. A resulting Hamiltonian to implement the scheme is derived, using only permutaion operators. Both a one-qubit gate and a two-qubit gate is derived, which forms a universal set allowing all possible quantum computation. The resulting scheme seems to only use two-body interactions. The project has shown that holonomic quantum computation in a noiseless subsystem using threephysical spin-1 particles is possible. The resulting scheme only using two-body interactions is of a large interest since this simplifies the experimental implementation.