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.     

Comment on: “Electromagnetic wave propagation in single-wall carbon nanotubes” [Phys. Lett. A 333 (2004) 303]

In a recent article [L. Wei, Y.-N. Wang, Phys. Lett. A 333 (2004) 303], Li Wei and You-Nian Wang studied the propagation of electromagnetic wave in single-wall carbon nanotubes and presented different expressions of the dispersions relations of TE and TM modes, respectively. Here we have derived the correct form of the dispersion relation for TM mode on low-frequency electromagnetic wave. It is shown numerically that asymptotic behaviours of the TM and TE modes are quite similar in single-wall carbon nanotubes.     

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 ‘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.     

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.     

Comment on “Piezonuclear decay of thorium” [Phys. Lett. A 373 (2009) 1956]

Subjecting a solution of ²²⁸Th to ultrasound (20 kHz, 100 W), Cardone et al. [F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956] claim to observe an increase in the transformation or decay rate of ²²⁸Th by a factor of 10⁴. The evidence provided seems however far from conclusive and in part contradictory to the claims made. In fact, looking at the presented data we find it cannot be taken as justification to discard the null hypothesis, namely, that the data from exposed and non-exposed samples are drawn from the same distribution. We suggest a number of additional tests that should be made in order to improve the quality of the study and test the hypothesis of so-called piezonuclear reactions.     

Comment on “Piezonuclear decay of thorium” [Phys. Lett. A 373 (2009) 1956]

Cardone et al. [F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956] claim that cavitation speeds up radioactive decay of ²²⁸Th dissolved in water. The experimental evidence they presented was criticized by Ericsson et al. [G. Ericsson, S. Pomp, H. Sjöstrand, E. Traneus, Phys. Lett. A 373 (2009) 3795]. This Comment focuses on a presumably-ignored trivial effect that might be responsible for the reported experimental results. It also contains suggestions for improving the quality of future investigations.     

Comment on: “Series solution to the Thomas-Fermi equation” [Phys. Lett. A 365 (2007) 111]

We discuss a recently proposed analytic solution to the Thomas-Fermi (TF) equation and show that earlier approaches provide more accurate results. In particular, we show that a simple and straightforward rational approximation to the TF equation yields the slope at origin with unprecedented accuracy, as well as remarkable values of the TF function and its first derivative for other coordinate values.     

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: ‘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.     

Comment on: “A class of bound entangled states” [Phys. Lett. A 352 (2006) 321]

We generalize the condition keeping the special states bound entangled [S.-M. Fei, X. Li-Jost, B.-Z. Sun, Phys. Lett. A 352 (2006) 321] to the general states. Taking the original 4×4$4\times 4$ states as 2×8$2\times 8$ states we show that they still can be bound entangled.     

Comment on: “Entanglement purification via controlled-controlled-NOT operations” [Phys. Lett. A 271 (2000) 44]

In this comment we show that some results presented by Feng et al. [X.-L. Feng, S.-Q. Gong, Z.-Z. Xu, Phys. Lett. A 271 (2000) 44] are incorrect.     

Comment on: “A simple chaotic delay differential equation” [Phys. Lett. A 366 (2007) 397]

The purpose of this Letter is to give the reference for the model proposed in the discussion section of the above paper [J.C. Sprott, Phys. Lett. A 366 (2007) 397] and to show that chaotic behavior of this model has been studied in [A. Uçar, Int. J. Eng. Sci. 40 (2002) 251; A. Uçar, Chaos Solitons Fractals 16 (2003) 187].     

Comment on “Remarks on the structure of states of composite quantum systems and envariance” [Phys. Lett. A 355 (2006) 180]

Let ρ∈S(H₁⊗H₂) with dim(H₁⊗H₂)=∞. Suppose that L:S(H₁⊗H₂)→S(H₁) is a map. It is asserted in [1] that if L satisfies the condition Tr(PL(ρ))=Tr((P⊗I₂)ρ) for all rank-one orthogonal projectors P∈B(H₁), then L is given by L(ρ)=Tr₂(ρ). However the proof in Blanchard and Bruning (2006) [1] is not correct. The purpose of this short Letter is to give a proof of this result.     

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 ‘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.