35,100 research outputs found

    On blowup formulae for the S-duality conjecture of Vafa and Witten

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    This is the first part of two papers. In this part, we prove the blowup formulae for virtual Hodge polynomials of Gieseker moduli spaces of rank-2 stable sheaves and Uhlenbeck compactification spaces over algebraic surfaces. In particular, we verify the blowup formulae for the S-duality conjecture of Vafa-Witten, i.e. the blowup formulae for the Euler numbers of instanton moduli spaces over algebraic surfaces.Comment: 24 page

    High-dimensional quantum state transfer in a noisy network environment

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    We propose and analyze an efficient high-dimensional quantum state transfer protocol in an XX coupling spin network with a hypercube structure or chain structure. Under free spin wave approximation, unitary evolution results in a perfect high-dimensional quantum swap operation requiring neither external manipulation nor weak coupling. Evolution time is independent of either distance between registers or dimensions of sent states, which can enable improvements in computational efficiency. In the low temperature regime and thermodynamic limit, the decoherence by noisy environment is studied with a model of an antiferromagnetic spin bath coupled to quantum channels via an Ising type interaction is studied. it is found that while the decoherence reduces the fidelity of state transfer, increasing intra-channel coupling can strongly suppress such effects. These observations demonstrate that robustness of the proposed scheme
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