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Register a new userComment on: The Casimir force on a piston in the spacetime with extra compactified dimensions [Phys. Lett. B 668 (2008) 72]
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We offer a clarification of the significance of the indicated paper of H. Cheng. Chengs conclusions about the attractive nature of Casimir forces between parallel plates are valid beyond the particular model in which he derived them; they are likely to be relevant to other recent literature on the effects of hidden dimensions on Casimir forces.
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In this paper we reply to the comment presented in [1]. In that work the author raises several points about the geometric phase for neutrinos discussed in [2]. He affirms that the calculation is flawed due to incorrect application of the definition of noncyclic geometric phase and the omission of one term in Wolfenstein effective Hamiltonian. He claims that the results are neither gauge invariant nor lepton field rephasing invariant and presents an alternative calculation, solely in order to demonstrate that the Majorana CP-violating phase enters the geometric phase essentially by lepton field rephasing transformation. Finally he claims that the nontrivial dependence of geometric phase on Majorana CP-violating phase presented in [2] is unphysical and thus unmeasurable. We discuss each of the points raised in [1] and show that they are incorrect. In particular, we introduce geometric invariants which are gauge and reparametrization invariants and show that the omitted term in the Wolfenstein effective Hamiltonian has no effect on them. We prove that the appearance of the Majorana phase cannot be ascribed to a lepton field rephasing transformation and thus the incorrectness of the claim of unphysicality and unmeasurability of the geometric phase. In the end we show that the calculation presented in [1] is inconsistent and based on the erroneous assumption and implementation of the wavefunction collapse. We remark that the geometric invariants defined in the present paper show a difference between Dirac and Majorana neutrinos, since they depend on the CP-violating Majorana phase.
We study the possibility that dark energy is a manifestation of the Casimir energy on extra dimensions with the topology of $S^2$. We consider our universe to be $M^4 times S^2$ and modify the geometry by introducing noncommutativity on the extra dimensions only, i.e. replacing $S^2$ with the fuzzy version $S_{F}^2$. We find the energy density as a function of the size of the representation $M+1$ of the algebra of $S_{F}^2$, and we calculate its value for the $M+1=2$ case. The value of the energy density turns out to be positive, i.e. provides dark energy, and the size of the extra dimensions agrees with the experimental limit. We also recover the correct commutative limit as the noncommutative parameter goes to zero.
Depending on the point of view, the Casimir force arises from variation in the energy of the quantum vacuum as boundary conditions are altered or as an interaction between atoms in the materials that form these boundary conditions. Standard analyses of such configurations are usually done in terms of ordinary, equal-time (Minkowski) coordinates. However, physics is independent of the coordinate choice, and an analysis based on light-front coordinates, where $x^+equiv t+z/c$ plays the role of time, is equally valid. After a brief historical introduction, we illustrate and compare equal-time and light-front calculations of the Casimir force.
In [J. T. Matta et al., Phys. Rev. Lett. 114, 082501 (2015)] a transverse wobbling band was reported in $^{135}$Pr. The critical experimental proof for this assignment is the E2 dominated linking transitions between the wobbling and normal bands, which are supported by two experiments performed with Gammasphere and INGA. However, the M1 dominated character cannot be excluded based on the reported experimental information, indicating that the wobbling assignment is still questionable.
The RENO experiment recently reported the disappearance of reactor electron antineutrinos consistent with neutrino oscillations, with a significance of 4.9 standard deviations. The published ratio of observed to expected number of antineutrinos in the far detector is R=0.920 +-0.009(stat.) +-0.014(syst.) and corresponds to sin^2 2theta13 = 0.113 +-0.013(stat.) +-0.019(syst), using a rate-only analysis. In this letter we reanalyze the data and we find a ratio R=0.903 +-0.01(stat.), leading to sin^2 2theta13 = 0.135. Moreover we show that the sin^2 2theta13 measurement still depend of the prompt high energy bound beyond 4 MeV, contrarily to the expectation based on neutrino oscillation.
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