35,100 research outputs found
On blowup formulae for the S-duality conjecture of Vafa and Witten
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
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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