Questions concerning the generalized Hartman effect

With reference to a particle tunneling through two successive barriers, it seems to have been generally accepted that the tunneling time does not depend on the separation distance between the barriers. This phenomenon has been called the generalized Hartman effect. In this Letter, we point out a lack of mathematical rigor in the reasoning by which this effect was deduced about ten years ago. A mathematically rigorous treatment shows us that the tunneling time does indeed depend on the length of the free space between the barriers.     

Comment on: “Questions concerning the generalized Hartman effect” [Phys. Lett. A 375 (2011) 3259]

In this comment, we show that the arguments against the applicability of stationary phase method (SPM) for tunneling time calculations, presented in Letter “Questions concerning the generalized Hartman effect” are not valid for small wave packet energy widths.     

Reply to “Comment on ‘Particle acceleration by stimulated emission of radiation near a solid-state medium’ [Phys. Lett. A 375 (2011) 256]”

We explain our assessment of electron acceleration in the vicinity of solid-state active medium based on current measurement which was criticized in the Comment by Dr. Nagaitsev. We also address a few comments raised by the referees.     

Reply to “Comment on ‘Piezonuclear decay of thorium’ [Phys. Lett. A 373 (2009) 1956]” [Phys. Lett. A 373 (2009) 3795]

In a paper appearing in this issue of Physics Letters A, Ericsson et al. raise some critical comments on the experiment [F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956] we carried out by cavitating a solution of thorium-228, which evidenced its anomalous decay behaviour, thus confirming the results previously obtained by Urutskoev et al. by explosion of titanium foils in solutions. In this Letter, we reply to these comments. In our opinion, the main shortcomings of the criticism by the Swedish authors are due to their omitting of inserting our experiment in the wider research stream of piezonuclear reactions, and to the statistical analysis they used, which does not comply with the rules generally accepted for samples with small numbers. However, apart from any possible theoretical speculation, there is the basic fact that two different experiments (ours and that by Urutskoev et al.), carried out independently and by different means, highlight an analogous anomaly in the decay of thorium subjected to pressure waves. Such a convergence of results shows that it is worth to further carry on experimental investigations, in order to get either a confirmation or a disproof of the induced-pressure anomalous behaviour of radioactive nuclides even different from thorium.     

Reply to “Comment on ‘Piezonuclear decay of thorium’ [Phys. Lett. A 373 (2009) 1956]” [Phys. Lett. A 374 (2009) 696]

In a Letter appearing in this issue of Physics Letters A, Kowalski raises some critical comments on the experiment [F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956] that we carried out by cavitating a solution of Thorium-228. The experiment highlighted the anomalous decay of Thorium, thus confirming the results previously obtained by Urutskoev et al. by explosion of titanium foils in solutions. In this Letter, we reply to these comments. We agree with Kowalski that critical comments are one of the key factors of the process to improve the quality of experiments and the interpretation of results. However we do hope that these comments together with the details provided in the replies will promote further and better experiments which are certainly worth performing in order to shed a brighter light on this issue, as Kowalski himself suggests in his comment.     

Comment on ‘Generalized Heisenberg algebra coherent states for power-law potentials’ [Phys. Lett. A 375 (3) (2011) 298]

We argue that the statistical features of generalized coherent states for power-law potentials based on Heisenberg algebra, presented in a recent paper by Berrada et al. (2011) [1] are incorrect.     

Reply to: “Comment on: ‘Epidemic spreading on heterogeneous networks with identical infectivity’ [Phys. Lett. A 364 (2007) 189]” [Phys. Lett. A 372 (2008) 1722]

In a recent Letter [R. Yang, B.H. Wang, J. Ren, W.J. Bai, Z.W. Shi, W.X. Wang, T. Zhou, Phys. Lett. A 364 (2007) 189], we proposed a modified susceptible-infected-recovered (SIR) model, in which each node is assigned with an identical capability of active contact, A, at each time step. We found a threshold value λc=1/A in uncorrelated and unlocalized networks. A corresponding Comment, raised by Alberto d'Onofrio, claimed that (i) our model is not biologically relevant; (ii) our model does not have a threshold behavior for recovered population; (iii) the analytical result λc=1/A is incorrect being considered as a threshold for epidemic outbreak, because of an improper approximation of the initial configuration. In this Reply, I show that, by debating from point to point, our analysis and conclusion are solid and reasonable.     

Reply to: “Comment on: ‘Efficient high-capacity quantum secret sharing with two-photon entanglement’ [Phys. Lett. A 372 (2008) 1957]” [Phys. Lett. A 373 (2009) 396]

A corresponding Comment, raised by Yang and Wen, claimed that (i) our scheme cannot complete the task of secret sharing well even if the agents obtain the information about their measuring bases; (ii) they give a feasible improvement of our protocol. In this Reply, we show that their first judgment is wrong and their improvement is insecure.     

Reply to “Comment on ‘Contextuality within quantum mechanics manifested in subensemble mean values’ [Phys. Lett. A 373 (2009) 3430]” [Phys. Lett. A 374 (2010) 1397]

In this reply, we point out that the claim by De Zela (2010) [2] is unjustified because the setup he discusses is not equivalent to the setup analysed in our paper (Pan and Home (2009) [1]). Hence his subsequent argument claiming the reproducibility of our demonstrated quantum effect of path-spin contextuality by the Kochen-Specker realist model is not relevant.     

Erratum to: “Comment on: ‘Electromagnetic wave propagation in single-wall carbon nanotubes’ [Phys. Lett. A 333 (2004) 303]” [Phys. Lett. A 364 (2007) 515]

Here we plot the correct form of Fig. 2 in [H. Khosravi, A. Moradi, Phys. Lett. A 364 (2007) 515].     

Reply to: “Comment on: ‘From classical to modern ether-drift experiments: the narrow window for a preferred frame’ [Phys. Lett. A 333 (2004) 355]” [Phys. Lett A 361 (2007) 509]

We present some arguments that should induce to re-consider from a new perspective the interference experiments in moving media (Michelson–Morley, Fizeau, …). These considerations are useful to understand and appreciate the experimental test recently proposed by Guerra and de Abreu.     

Reply to: “Comment on: ‘Effects of including the counterrotating term and virtual photons on the eigenfunctions and eigenvalues of a scalar photon collective emission theory’ [Phys. Lett. A 372 (2008) 2514]” [Phys. Lett. A 372 (2008) 5732]

We compute the emission amplitude for the collective emission from a sphere of identical atoms in the scalar photon theory for both the cases of the complex kernel (i.e. including virtual photons) and real kernel. We explicitly show that the single mode theory based on the real kernel neglects the effects of the different decay rates and frequency shifts associated with the eigenfunctions belonging to the same angular index but with different radial indices. We show that these effects modify, for k₀R?1, both the time dependence of the emission amplitude and its angular distribution, in clear contradiction to the assertions made by the Comment's authors.