5,408 research outputs found
Neutral Particles and Super Schwinger Terms
Z_2-graded Schwinger terms for neutral particles in 1 and 3 space dimensions
are considered.Comment: 13 page
Out of equilibrium correlations in the XY chain
We study the transversal XY spin-spin correlations in the non-equilibrium
steady state constructed in \cite{AP03} and prove their spatial exponential
decay close to equilibrium
Evolution of Non-linear Fluctuations in Preheating after Inflation
We investigate the evolution of the non-linear long wavelength fluctuations
during preheating after inflation. By using the separate universe approach, the
temporal evolution of the power spectrum of the scalar fields and the curvature
variable is obtained numerically. We found that the amplitude of the large
scale fluctuations is suppressed after non-linear evolution during preheating.Comment: To be published in Class. Quantum Gra
Search for the Invisible Decay of Neutrons with KamLAND
The Kamioka Liquid scintillator Anti-Neutrino Detector is used in a search for single neutron or two-neutron intranuclear disappearance that would produce holes in the s-shell energy level of ^(12)C nuclei. Such holes could be created as a result of nucleon decay into invisible modes (inv), e.g., n→3ν or nn→2ν. The deexcitation of the corresponding daughter nucleus results in a sequence of space and time-correlated events observable in the liquid scintillator detector. We report on new limits for one- and two-neutron disappearance: τ(n→inv) > 5.8 × 10^(29) years and τ(nn→inv) > 1.4 × 10^(30) years at 90% C.L. These results represent an improvement of factors of ~3 and > 10^4 over previous experiments
Measurement of neutrino oscillation with KamLAND: Evidence of spectral distortion
We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 v_e candidate events with energies above 3.4 MeV compared to 365.2±23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8±7.3 expected background events, the statistical significance for reactor v_e over bar (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from v_e oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Δm^2=7.9_(-0.5)^(+0.6)x10^(-5) eV^2. A global analysis of data from KamLAND and solar-neutrino experiments yields
Δm^2=7.9_(-0.5)^(+0.6)x10^(-5) eV^2 and tan^2θ=0.40_(-0.07)^(+0.10), the most precise determination to date
The H\"older Inequality for KMS States
We prove a H\"older inequality for KMS States, which generalises a well-known
trace-inequality. Our results are based on the theory of non-commutative
-spaces.Comment: 10 page
Kakutani Dichotomy on Free States
Two quasi-free states on a CAR or CCR algebra are shown to generate
quasi-equivalent representations unless they are disjoint.Comment: 12 page
A proof of the generalized second law for rapidly changing fields and arbitrary horizon slices
The generalized second law is proven for semiclassical quantum fields falling
across a causal horizon, minimally coupled to general relativity. The proof is
much more general than previous proofs in that it permits the quantum fields to
be rapidly changing with time, and shows that entropy increases when comparing
any slice of the horizon to any earlier slice. The proof requires the existence
of an algebra of observables restricted to the horizon, satisfying certain
axioms (Determinism, Ultralocality, Local Lorentz Invariance, and Stability).
These axioms are explicitly verified in the case of free fields of various
spins, as well as 1+1 conformal field theories. The validity of the axioms for
other interacting theories is discussed.Comment: 44 pages, 1 fig. v3: clarified Sec. 2; signs, factors/notation
corrected in Eq. 75-80, 105-107; reflects published version. v4: clearer
axioms in Sec. 2.3, fixed compensating factor of 2 errors in Eq. 54,74 etc.,
and other errors. Results unaffected. v5: fixed typos. v6: replaced faulty
1+1 CFT argument, added note on recent progres
Discrete R-symmetry anomalies in heterotic orbifold models
Anomalies of discrete R-symmetries appearing in heterotic orbifold models are
studied. We find that the mixed anomalies for different gauge groups satisfy
the universal Green-Schwarz (GS) condition, indicating that these anomalies are
canceled by the GS mechanism. An exact relation between the anomaly
coefficients of the discrete R-symmetries and one-loop beta-function
coefficients is obtained. We also find that the discrete R-symmetries have a
good chance to be unbroken down to the supersymmetry breaking scale. Even below
this scale a subgroup is unbroken, which may be an origin of the R-parity
of the minimal supersymmetric standard model. Relations between the R-symmetry
anomalies and T-duality anomalies are also investigated.Comment: 19 pages, no figur
Quantizing the damped harmonic oscillator
We consider the Fermi quantization of the classical damped harmonic
oscillator (dho). In past work on the subject, authors double the phase space
of the dho in order to close the system at each moment in time. For an
infinite-dimensional phase space, this method requires one to construct a
representation of the CAR algebra for each time. We show that unitary dilation
of the contraction semigroup governing the dynamics of the system is a logical
extension of the doubling procedure, and it allows one to avoid the
mathematical difficulties encountered with the previous method.Comment: 4 pages, no figure
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