627 research outputs found
Analytic Continuation of Resolvent Kernels on noncompact Symmetric Spaces
Let X=G/K be a symmetric space of noncompact type and let L be the Laplacian
associated with a G-invariant metric on X. We show that the resolvent kernel of
L admits a holomorphic extension to a Riemann surface depending on the rank of
the symmetric space. This Riemann surface is a branched cover of the complex
plane with a certain part of the real axis removed. It has a branching point at
the bottom of the spectrum of L. It is further shown that this branching point
is quadratic if the rank of X is odd, and is logarithmic otherwise. In case G
has only one conjugacy class of Cartan subalgebras the resolvent kernel extends
to a holomorphic function on a branched cover of the complex plane with the
only branching point being the bottom of the spectrum.Comment: 16 pages, 3 figures, LaTe
I giovani a bassa scolarità in due quartieri torinesi
Working Paper ; n.104- Indice #3- Giovani a bassa scolarità a Torino: un problema degli anni '90 #5- Lavoro e scolarità nei giovani torinesi #7- Giovani a bassa scolarità nei quartieri S.Donato e Regio Parco #23- Approfondimenti. I giovani e la scuola #33- I giovani nel quartiere San Donato #35- I giovani el quartiere Regio Parco/Barca/Bertolla #53- La scuola a S. Donato #65- La scuola a Regio Parco/Barca/Bertola #89- Appendice: le circoscrizioni di riferimento #10
High-contrast dark resonance on the D2 - line of 87Rb in a vapor cell with different directions of the pump - probe waves
We propose a novel method enabling to create a high-contrast dark resonance
in the 87Rb vapor D2-line. The method is based on an optical pumping of atoms
into the working states by a two-frequency, linearly-polarized laser radiation
propagating perpendicularly to the probe field. This new scheme is compared to
the traditional scheme involving the circularly-polarized probe beam only, and
significant improvement of the dark resonance parameters is found. Qualitative
considerations are confirmed by numerical calculations.Comment: 7 pages, 4 figure
Bergers des plains de Léon [Material gráfico]= Shepherds of the plains of León
Lámina coloreada al aguatintaCopia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201
Scaling of the spin stiffness in random spin-1/2 chains : Crossover from pure-metallic behaviour to random singlet-localized regime
In this paper we study the localization transition induced by the disorder in
random antiferromagnetic spin-1/2 chains. The results of numerical large scale
computations are presented for the XX model using its free fermions
representation. The scaling behavior of the spin stiffness is investigated for
various disorder strengths. The disorder dependence of the localization length
is studied and a comparison between numerical results and bosonization
arguments is presented. A non trivial connection between localization effects
and the crossover from the pure XX fixed point to the infinite randomness fixed
point is pointed out.Comment: Published version, 7 pages, 6 figure
A student of the Irish College, Salamanca [Material gráfico]
Lámina coloreada al aguatintaCopia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2010-201
Intérieur de l'Église de St. Dominique de Salamanque [Material gráfico]= Interior of the Dominican Church, Salamanca
Lámina coloreada al aguatintaCopia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201
Secure direct communication using Einstein-Podolsky-Rosen pairs and teleportation
A novel scheme for secure direct communication between Alice and Bob is
proposed, where there is no need for establishing a shared secret key. The
communication is based on Einstein-Podolsky-Rosen pairs and teleportation
between Alice and Bob. After insuring the security of the quantum channel (EPR
pairs), Bob encodes the secret message directly on a sequence of particle
states and transmits them to Alice by teleportation. In this scheme
teleportation transmits Bob's message without revealing any information to a
potential eavesdropper. Alice can read out the encoded messages directly by the
measurement on her qubits. Because there is not a transmission of the qubit
which carry the secret message between Alice and Bob, it is completely secure
for direct secret communication if perfect quantum channel is used
Paysan en habit de paille [Material gráfico]= Peasant in a straw coat
Lámina coloreada al aguatintaCopia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201
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