45,296 research outputs found
Using Simon's Algorithm to Attack Symmetric-Key Cryptographic Primitives
We present new connections between quantum information and the field of
classical cryptography. In particular, we provide examples where Simon's
algorithm can be used to show insecurity of commonly used cryptographic
symmetric-key primitives. Specifically, these examples consist of a quantum
distinguisher for the 3-round Feistel network and a forgery attack on CBC-MAC
which forges a tag for a chosen-prefix message querying only other messages (of
the same length). We assume that an adversary has quantum-oracle access to the
respective classical primitives. Similar results have been achieved recently in
independent work by Kaplan et al. Our findings shed new light on the
post-quantum security of cryptographic schemes and underline that classical
security proofs of cryptographic constructions need to be revisited in light of
quantum attackers.Comment: 14 pages, 2 figures. v3: final polished version, more formal
definitions adde
Resonant charging of Xe clusters in Helium nanodroplets under intense laser fields
We theoretically investigate the impact of multiple plasmon resonances on the
charging of Xe clusters embedded in He nanodroplets under intense pump-probe
laser excitation. Our molecular dynamics simulations on Xe309He10000 give clear evidence for selective
resonance heating in the He shell and the Xe cluster, but no corresponding
double hump feature in the final Xe charge spectra is found. Though the
presence of the He shell substantially increases the maximum charge states, the
pump-probe dynamics of the Xe spectra from embedded system is similar to that
of the free species. In strong contrast to that, the predicted electron spectra
do show well-separated and pronounced features from highly efficient plasmon
assisted electron acceleration for both resonances in the embedded clusters. A
detailed analysis of the underlying ionization and recombination dynamics is
presented and explains the apparent disaccord between the resonance features in
the ion and electron spectra.Comment: revised manuscrip
Logarithmic Frobenius manifolds, hypergeometric systems and quantum D-modules
We describe mirror symmetry for weak toric Fano manifolds as an equivalence
of D-modules equipped with certain filtrations. We discuss in particular the
logarithmic degeneration behavior at the large radius limit point, and express
the mirror correspondence as an isomorphism of Frobenius manifolds with
logarithmic poles. The main tool is an identification of the Gauss-Manin system
of the mirror Landau-Ginzburg model with a hypergeometric D-module, and a
detailed study of a natural filtration defined on this differential system. We
obtain a solution of the Birkhoff problem for lattices defined by this
filtration and show the existence of a primitive form, which yields the
construction of Frobenius structures with logarithmic poles associated to the
mirror Laurent polynomial. As a final application, we show the existence of a
pure polarized non-commutative Hodge structure on a Zariski open subset of the
complexified Kaehler moduli space of the variety
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