1870101
Local temperature in curved spacetime
A physically meaningful local concept of temperature is introduced in quantum field theory on curved spacetime and applied to the example of a massless field on de Sitter space. It turns out in this model that the equilibrium (Gibbs) states which can be prepared by a geodesic observer have in general a varying temperature distribution in the neighbourhood of the geodesic and may not even allow for a consistent thermal interpretation close to the horizon. This result, which can be traced back to the Unruh effect, illustrates the failure of a global notion of temperature in curved spacetime and reveals the need for a local concept, as presented here.
54540534
How small is the phase space in quantum field theory
The existing compactness and nuclearity conditions characterizing phase space properties of a quantum field theory are compared and found to be particularly sensitive either in the infrared or the ultraviolet domain. A sharpened condition combining both features is proposed and shown to be satisfied in free field theory in four space-time dimensions Nous comparons les conditions connues de compacite et de nuclearite qui caracterisent les proprietes d'espace de phase d'une theorie quantique des champs. Nous montrons qu'elles sont particulierement adaptees soit au domaine ultraviolet ou infrarouge. Nous proposons une nouvelle condition qui combine ces deux aspects et qui est verifiee pour le champ libre en dimension quatre
11892514
An Algebraic Characterization of Vacuum States in Minkowski Space. III. Reflection Maps
Employing the algebraic framework of local quantum physics, vacuum states in Minkowski space are distinguished by a property of geometric modular action. This property allows one to construct from any locally generated net of observables and corresponding state a continuous unitary representation of the proper Poincaré group which acts covariantly on the net and leaves the state invariant. The present results and methods substantially improve upon previous work. In particular, the continuity properties of the representation are shown to be a consequence of the net structure, and surmised cohomological problems in the construction of the representation are resolved by demonstrating that, for the Poincaré group, continuous reflection maps are restrictions of continuous homomorphisms.
1050696
Towards a relativistic KMS-condition
Abstract It is shown that, under quite general conditions, thermal correlation functions in relativistic quantum field theory have stronger analyticity properties in configuration space than those imposed by the KMS-condition. These analyticity properties may be understood as a remnant of the relativistic spectrum condition in the vacuum sector and lead to a Lorentz-covariant formulation of the KMS-condition involving all space-time variables.
354449
The Resolvent Algebra: A New Approach to Canonical Quantum Systems
The standard C*–algebraic version of the algebra of canonical commutation relations, the Weyl algebra, frequently causes difficulties in applications since it neither admits the formulation of physically interesting dynamical laws nor does it incorporate pertinent physical observables such as (bounded functions of) the Hamiltonian. Here a novel C*–algebra of the canonical commutation relations is presented which does not suffer from such problems. It is based on the resolvents of the canonical operators and their algebraic relations. The resulting C*–algebra, the resolvent algebra, is shown to have many desirable analytic properties and the regularity structure of its representations is surprisingly simple. Moreover, the resolvent algebra is a convenient framework for applications to interacting and to constrained quantum systems, as we demonstrate by several examples.
120571075
Local properties of equilibrium states and the particle spectrum in quantum field theory
AbstractIt is shown that in a quantum field theory describing free, scalar particles with masses mi, i∈ℕ there exist locally normal equilibrium states with finite energy density for all temperature β>0 if and only if 
$$\Sigma _{i = 1}^\infty {\text{ e}}^{ - \beta m_i } < \infty $$
. This result lends support to the conjecture that the nuclearity criterion proposed by Buchholz and Wichmann is sensitive to the thermodynamical properties of field-theoretic models.
120539815
Experimental tests of discrete symmetries in the decays k+- ---> pi+ pi- e+- nu(e)
118465845
Recent results on charm from Fermilab experiment E-687
About 10{sup 4} charm decays have been reconstructed from first-run data of Fermilab experiment E687 using the Fermilab Wide-Band Photon Spectrometer with the world's highest energy photon beam. The success of techniques for isolating and reconstructing charm event samples based on two complementary vertexing strategies is illustrated. Preliminary results are presented. These include lifetime value of (0.50 {plus minus} 0.06 {plus minus} 0.03)ps for the D{sub s}{sup +}, and (0.20 {plus minus} 0.03 {plus minus} 0.03)ps for the {Lambda}{sub c}{sup +}. Preliminary values for the D{sup +} and D{sup 0} lifetimes are consistent with currently accepted world averages. Signals for the Cabibbo-suppressed decays D{sup 0} {yields} {pi}{sup +}{pi}{sup {minus}}{pi}{sup +}{pi}{sup {minus}}, D{sup +} {yields} K{sup +}K{sup {minus}}{pi}{sup +}, and D{sup +} {yields} {phi}{pi}{sup +} are shown; for B(D{sup 0} {yields} {pi}{sup +}{pi}{sup {minus}}{pi}{sup +}{pi}{sup {minus}})/B(D{sup 0} {yields} K{sup {minus}}{pi}{sup +}{pi}{sup +}{pi}{sup {minus}}) our preliminary value is 0.10 {plus minus} 0.02 {plus minus} 0.02. Preliminary values for ratios B(D{sup 0} {yields} {ovr K}{sup 0}K{sup +}K{sup {minus}})/B(D{sup 0} {yields} {ovr K}{sup 0}{pi}{sup +}{pi}{sup {minus}}) and B(D{sup 0} {yields} {ovr K}{sup 0}{phi})/B(D{sup 0} {yields} {ovr K}{sup 0}{pi}{sup +}{pi}{sup {minus}}) are 0.20 {plus minus} 0.06 and 0.16 {plus minus} 0.06. Preliminary results are givenmore » for cross sections of D*{sup {plus minus}} and D{sup {plus minus}} photoproduction on a Be target for the p{sup 2}{sub {tau}} dependence of D{sup {minus plus}} photoproduction and for the ratios D{double prime}/D*{sup +} and D*{sup {minus}}/D{sup {minus plus}}. The energy dependence of the total open charm photoproduction cross section is compared with model predictions for photon energies up to 350 GeV. 18 refs., 5 figs.« less
121765828
Pion pion phase shift and form-factors in the decays k+- ---> pi+ pi- e+- nu(e)
119779374
Neural network based neutral particles reconstruction with the E687 hadron calorimeter
Abstract We present a neutral particle reconstruction algorithm based on a neural network approach applied to the E687 hadron calorimeter. A measurement of the invariant mass of the Σ ± → nπ ± is presented to verify the reliability of the reconstruction. The reconstructed invariant mass of the charmed meson D + → K L 0 π + π + π − is also presented to show the possible application of this technique to charmed particles decaying into a neutral hadron. An example of this would be Λ c + → n K − π + π + .
110772906
The use of waveform digitizers with drift chambers for D0
Abstract A prototype drift chamber cell with good space resolution, d E d x , and two particle separation has been constructed. A 100 MHz, 11 bit waveform digitizer readout scheme has been used for the tests.