1,721,127 research outputs found
Kähler fibrations in quantum information theory
No full textWe discuss the fibre bundle of co-adjoint orbits of compact Lie groups, and show how it admits a compatible Kähler structure. The case of the unitary group allows us to reformulate the geometric framework of quantum information theory. In particular, we show that the Fisher information tensor gives rise to a structure that is sufficiently close to a Kähler structure to generalise some classical result on co-adjoint orbits
On the geometry of mixed states and the Fisher information tensor
No full textIn this paper, we will review the co-adjoint orbit formulation of finite dimensionalquantum mechanics, and in this framework, we will interpret the notion of quantumFisher information index (and metric). Following previous work of part of theauthors, who introduced the definition of Fisher information tensor, we will showhow its antisymmetric part is the pullback of the natural Kostant-Kirillov-Souriausymplectic form along some natural diffeomorphism. In order to do this, we willneed to understand the symmetric logarithmic derivative as a proper 1-form, settlingthe issues about its very definition and explicit computation. Moreover, the fibrationof co-adjoint orbits, seen as spaces of mixed states, is also discussed
Towards Holography in the BV-BFV Setting
No full textWe show how the BV-BFV formalism provides natural solutions to descent equations and discuss how it relates to the emergence of holographic counterparts of given gauge theories. Furthermore, by means of an AKSZ-type construction we reproduce the Chern–Simons to Wess–Zumino–Witten correspondence from infinitesimal local data and show an analogous correspondence for BF theory. We discuss how holographic correspondences relate to choices of polarisation relevant for quantisation, proposing a semi-classical interpretation of the quantum holographic principle
Relapsing polychondritis
No full textRelapsing polychondritis is a rare disease of unknown origin consisting in recurrent inflammatory episodes of cartilaginous structures as well as other organs such as the eye, the inner ear and the kidney. Symptoms of autoimmune or rheumatic disorders frequently precede those typical of relapsing polychondritis and thus the contemporaneous presence of these diseases is a common observation. Consequently some diagnostic concerns connected to the great variability of the early symptoms and also to the lack of a semiotic test do exist. It is widely recognized that a serious involvement of the tracheo-bronchial cartilage the lumen diameter with a consequent heavy dyspnoea which reduces occurs in relapsing polychondritis. In these cases the study of the thorax area by means of CT was of fundamental importance. Furthermore, histological analysis of bioptic specimens from tissues only apparently not affected, such as the pinna of the ears, better defines the nature of the disease. The Authors present a case report, characterized by the presence of a saddle-nose deformity as well as a dyspnoea caused by a lumen stenosis related to tracheo-bronchial cartilage chondritis
[Relapsing polychondritis]
No full textRelapsing polychondritis is a rare disease of unknown origin consisting in recurrent inflammatory episodes of cartilaginous structures as well as other organs such as the eye, the inner ear and the kidney. Symptoms of autoimmune or rheumatic disorders frequently precede those typical of relapsing polychondritis and thus the contemporaneous presence of these diseases is a common observation. Consequently some diagnostic concerns connected to the great variability of the early symptoms and also to the lack of a semiotic test do exist. It is widely recognized that a serious involvement of the tracheo-bronchial cartilage the lumen diameter with a consequent heavy dyspnoea which reduces occurs in relapsing polychondritis. In these cases the study of the thorax area by means of CT was of fundamental importance. Furthermore, histological analysis of bioptic specimens from tissues only apparently not affected, such as the pinna of the ears, better defines the nature of the disease. The Authors present a case report, characterized by the presence of a saddle-nose deformity as well as a dyspnoea caused by a lumen stenosis related to tracheo-bronchial cartilage chondritis
BV analysis of Polyakov and Nambu–Goto theories with boundary
No full textISSN:0377-9017ISSN:1573-0530ISSN:1573-053
Boundary structure of general relativity in tetrad variables
No full textAn explicit, geometric description of the first-class constraints and their Poisson brackets for gravity in the Palatini–Cartan formalism (in space–time dimension greater than three) is given. The corresponding Batalin–Fradkin–Vilkovisky (BFV) formulation is also develope
Symmetric logarithmic derivative for general n-level systems and the quantum Fisher information tensor for three-level systems
Full text linkWithin a geometrical context, we derive an explicit formula for the computation of the symmetric logarithmic derivative for arbitrarily mixed quantum systems, provided that the structure constants of the associated unitary Lie algebra are known. To give examples of this procedure, we first recover the known formulae for two-level mixed and three-level pure state systems and then apply it to the novel case of U(3)U(3), that is for arbitrarily mixed three-level systems (q-trits). Exploiting the latter result, we finally calculate an expression for the Fisher tensor for a q-trit considering also all possible degenerate subcases
A general construction for monoid-based knapsack protocols
Full text linkWe present a generalized version of the knapsack protocol proposed by D. Naccache and J. Stern at the Proceedings of Eurocrypt (1997). Our new framework will allow the construction of other knapsack protocols having similar security features. We will outline a very concrete example of a new protocol using extension fields of a finite field of small characteristic instead of the prime field Z/pZ, but more efficient in terms of computational costs for asymptotically equal information rate and similar key size
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