A revised controlled deterministic secure quantum communication with five-photon entangled state

A revised controlled deterministic secure quantum communication protocol using five-photon entangled state is proposed. It amends the security loopholes pointed by Qin et al. in [S.J. Qin, Q.Y. Wen, L.M. Meng, F.C. Zhu, Opt. Commun. 282 (2009) 2656] in the original protocol proposed by Xiu et al. in [X.M. Xiu, L. Dong, Y.J. Gao, F. Chi, Opt. Commun. 282 (2009) 333]. The security loopholes are solved by using order rearrangement of transmission photons and two-step security test.     

Discrimination of surface and bulk scattering of arbitrary level based on angle-resolved ellipsometry: Theoretical analysis

An experimental procedure, which was found to be valid for both low-level and high-level scattering of random media, was recently shown to directly discriminate between surface and bulk scattering origin [O. Gilbert, C. Deumie, C. Amra, Angle-resolved ellipsometry of scattering patterns from arbitrary surfaces and bulk materials, Opt. Express 13 (2005) 2403]. The method is based on the ellipsometric measurement of the scattered field over the scattering angle and the analysis of the obtained relative phase shift between s and p polarizations. In the case of low-level scattering, the results were already known and have been explained by first order electromagnetic theories. However, information detailing high-level scattering is scarce. Using rigorous electromagnetic theory, we examined high-level scattering. The differential method enabled us to validate the experimental observations of Gilbert et al. (2005) and explore the limits of validity of the discrimination technique.     

Erratum: Arbitrated quantum signature of classical messages against collective amplitude damping noise (Opt. Commun. 283 (2010) 3198-3201)

We discover an error in the quantum circuit in Fig. 2 in the original paper [Y.G. Yang, Q.Y. Wen. Opt. Commun. 283 (2010) 3198-3201]. Corrected results are obtained and presented in this paper.     

Comment on "Wide-field coherent anti-Stokes Raman scattering microscopy with non-phase-matching illumination"

We comment on a Letter by Toytman et al. [Opt. Lett.32, 1941 (2007)] in which a novel setup for wide-field imaging in coherent anti-Stokes Raman scattering (CARS) microscopy is demonstrated. There the authors state that our phase-matching implementation of a wide-field CARS system [Appl. Phys. Lett.84, 816 (2004); New J. Phys.8, 36 (2006)] suffers from a strong background from the bulk medium. However, our results show quite the contrary, i.e., that our setup provides a very good signal contrast, due to an almost vanishing background level from the bulk solvent.     

Comment on “Eavesdropping on the improved three-party quantum secret sharing protocol”

In the comment, we show that the attack [G. Gao, Opt. Commun. 43 (2010) 902], which claims to be able to eavesdrop all the transmitted secret message of the improved three-party quantum secret sharing protocol [S. Lin, et al., Opt. Commun. 281 (2008) 4553], is invalid in the sense that it introduces 25% error rate.     

Simple Collaboration Eavesdropping on the Improved Multiparty Quantum Secret Sharing Protocol

We propose a new attack strategy for the improvement n-party (n≥4) case [S. Lin, F. Gao, Q.Y. Wen, F.C. Zhu in Opt. Commun. 281:4553, 2008] of the multiparty quantum secret sharing protocol [Z.J. Zhang, G. Gao, X. Wang, L.F. Han, S.H. Shi in Opt. Commun. 269:418, 2007]. Our attack strategy is an interesting collaboration eavesdropping and much simpler than that in the paper [T.Y. Wang, Q.Y. Wen, F. Gao, S. Lin, F.C. Zhu in Phys. Lett. A 373:65, 2008].     

Top Quark Flavor Changing Decay t

[1]R. Casalbuoani, A. Deandrea, and M. Oertel, JHEP 032(2004) 0402. [2]G. Hooft, In Search of the Ultimate Building Blocks, Cambridge University Press, Cambridge (1997). [3]J. Belazey, Searches for New Physics at Hadron Coliders,Northern Illinois University (2005). [4]N. Arkani-hamed, A.G. Cohen, and H. Georgi, Phys. Lett.B 513 (2001) 232 [hep-ph/0105239]. [5]I. Low, W. Skiba, and D. Smith, Phys. Rev. D 66 (2002)072001 [hep-ph/0207243]. [6]N. Arkani-hamed, A.G. Cohen, E. Katz, and A.E. Nelson,JHEP 0207 (2002) 304 [hep-ph/0206021]. [7]N. Arkani-hamed, A.G. Cohen, E. Katz, A.E. Nelson, T.Gregoire, and J. G. Wacker, JHEP 0208 (2002) 021 [hepph/0206020]. [8]T. Gregoire and J.G. Wacker, JHEP 0208 (2002) 019[hep-ph/0206023]. [9]For a recent review, see e.g., M. Schmaltz, Nucl. Phys. B (Proc. Suppl.) 117 (2003) 40. [10]N. Arkani-hamed, A.G. Cohen, T. Gregoire, and J.G.Jacker, JHEP 0208 (2002) 020 [hep-ph/0202089]. [11]or a recent review, see e.g., M. Schmaltz, Nucl. Phys.Proc. Suppl. 117 (2003) 40 [hep-ph/0210415]. [12]E. Katz, J. Lee, A.E. Nelson, and D.G. Walker, hepph/0312287. [13]M. Beneke, I. Efthymiopoulos, M.L. Mangano, et al., hepph/0003033. [14]D.O. Carlson and C.-P. Yuan, hep-ph/9211289. [15]R. Frey, D. Gerdes, and J. Jaros, hep-ph/9704243. [16]G. Eilam, J.L. Hewett, and A. Soni, Phys. Rev. D 44(1991) 1473; W.S. Hou, Phys. Lett. B 296 (1992) 179; K.Agashe and M. Graesser, Phys. Rev. D 54 (1996) 4445;M. Hosch, K. Whisnant, and B.L. Young, Phys. Rev. D56 (1997) 5725. [17]C.S. Li, R.J. Oakes, and J.M. Yang, Phys. Rev. D 49(1994) 293, Erratum-ibid. D 56 (1997) 3156; G. Couture,C. Hamzaoui, and H. Koenig, Phys. Rev. D 52 (1995)1713; G. Couture, M. Frank, and H. Koenig, Phys. Rev.D 56 (1997) 4213; G.M. de Divitiis, et al., Nucl. Phys. B 504 (1997) 45. [18]B. Mele, S. Petrarca, and A. Soddu, Phys. Lett. B 435(1998) 401. [19]B. Mele, hep-ph/0003064. [20]J.M. Yang and C.S. Li, Phys. Rev. D 49 (1994) 3412,Erratum, ibid. D 51 (1995) 3974; J.G. Inglada, hepph/9906517. [21]L.R. Xing, W.G. Ma, R.Y. Zhang, Y.B. Sun, and H.S.Hou, Commun. Theor. Phys. (Beijing, China) 41 (2004)241. [22]L.R. Xing, W.G. Ma, R.Y. Zhang, Y.B. Sun, and H.S.Hou, Commun. Theor. Phys. (Beijing, China) 40 (2003)171. [23]T. Han, H.E. Logan, B. McElrath, and L.T. Wang, Phys.Rev. D 67 (2003) 095004. [24]I. Low, W. Skiba, and D. Smith, Phys. Rev. D 66 (2002)072001. [25]T. Han, H.E. Logan, B. McElrath, and L.T. Wang, hepph/0302188. [26]A.J. Buras, A. Poschenrieder, and S. Uhlig, hepph/0410309. [27]S. Eidelman, et al., Phys. Lett. B 592 (2004) 1. [28]F. Legerlehner, DESY 01-029, hep-ph/0105283.     

High harmonic generation in a gas-filled hollow-core photonic crystal fiber

High harmonic generation (HHG) of intense infrared laser radiation (Ferray et al., J. Phys. B: At. Mol. Opt. Phys. 21:L31, 1988; McPherson et al., J. Opt. Soc. Am. B 4:595, 1987) enables coherent vacuum-UV (VUV) to soft-X-ray sources. In the usual setup, energetic femtosecond laser pulses are strongly focused into a gas jet, restricting the interaction length to the Rayleigh range of the focus. The average photon flux is limited by the low conversion efficiency and the low average power of the complex laser amplifier systems (Keller, Nature 424:831, 2003; Südmeyer et al., Nat. Photonics 2:599, 2008; Röser et al., Opt. Lett. 30:2754, 2005; Eidam et al., IEEE J. Sel. Top. Quantum Electron. 15:187, 2009) which typically operate at kilohertz repetition rates. This represents a severe limitation for many experiments using the harmonic radiation in fields such as metrology or high-resolution imaging. Driving HHG with novel high-power diode-pumped multi-megahertz laser systems has the potential to significantly increase the average photon flux. However, the higher average power comes at the expense of lower pulse energies because the repetition rate is increased by more than a thousand times, and efficient HHG is not possible in the usual geometry. So far, two promising techniques for HHG at lower pulse energies were developed: external build-up cavities (Gohle et al., Nature 436:234, 2005; Jones et al., Phys. Rev. Lett. 94:193, 2005) and resonant field enhancement in nanostructured targets (Kim et al., Nature 453:757, 2008). Here we present a third technique, which has advantages in terms of ease of HHG light extraction, transverse beam quality, and the possibility to substantially increase conversion efficiency by phase-matching (Paul et al., Nature 421:51, 2003; Ren et al., Opt. Express 16:17052, 2008; Serebryannikov et al., Phys. Rev. E (Stat. Nonlinear Soft Matter Phys.) 70:66611, 2004; Serebryannikov et al., Opt. Lett. 33:977, 2008; Zhang et al., Nat. Phys. 3:270, 2007). The interaction between the laser pulses and the gas occurs in a Kagome-type Hollow-Core Photonic Crystal Fiber (HC-PCF) (Benabid et al., Science 298:399, 2002), which reduces the detection threshold for HHG to only 200 nJ. This novel type of fiber guides nearly all of the light in the hollow core (Couny et al., Science 318:1118, 2007), preventing damage even at intensities required for HHG. Our fiber guided 30-fs pulses with a pulse energy of more than 10 μJ, which is more than five times higher than for any other photonic crystal fiber (Hensley et al., Conference on Lasers and Electro-Optics (CLEO), IEEE Press, New York, 2008).     

Improving the quantum secure direct communication by entangled qutrits and entanglement swapping against intercept-and-resend attack

The security of quantum secure direct communication by entangled qutrits and entanglement swapping [Y.B. Zhan et al., Opt. Commun. 282 (2009) 4633] is analyzed. It is shown that an eavesdropper can obtain all the secret without being found by a simple intercept-and-resend attack. Finally, a possible improvement to resist this attack is proposed.     

Information leakage in three-party simultaneous quantum secure direct communication with EPR pairs

In 2007, Wang et al. [M. Y. Wang and F. L. Yan, Chin. Phys. Lett. 24 (2007) 2486] proposed a three-party simultaneous quantum secure direct communication (3P-SQSDC) scheme with EPR pairs. Recently, Chong et al. [S. K. Chong and T. Hwang, Opt. Commun. OPTICS-15438 (2010(online))] proposed an enhancement on Wang et al.'s scheme. The communications in Chong et al.'s 3P-SQSDC can be paralleled and thus their scheme has higher efficiency. However, we find that both of the schemes have the information leakage, because the legitimate parties' secret messages have a strong correlation. This kind of security loophole leads to the consequence that any eavesdropper (Eve) can directly conjecture some information about the secrets without any active attack.     

Schemes to generate and distinguish a type of genuine four-qubit entangled states in a cavity QED system

We propose a scheme to generate a type of genuine four-qubit entangled states, which were firstly introduced by Yeo et al. [Y. Yeo, W. K. Chua, Phys. Rev. Lett. 96 (2006) 060502]. These states have many interesting entanglement properties and possess possible applications in quantum information processing and in fundamental tests of quantum physics. We show that such a type of 16 orthonormal basis states can be deterministically distinguished by a cavity QED system.     

Cryptanalysis and improvement of multiparty quantum secret sharing schemes

A scheme of multiparty quantum secret sharing of classical messages (QSSCM) [Z.J. Zhang et al., Opt. Commun. 269 (2007) 418] was proposed. Lin et al. [S. Lin et al., Opt. Commun. 281 (2008) 4553] showed the last agent can obtain half of the secret in Z.J. Zhang's et al. three-party QSSCM scheme and gave an improved version. We further show the first agent and the last agent can obtain all the secret without introducing any error in Zhang's et al. multiparty QSSCM scheme by a special attack with quantum teleportation. We also present an improved version.     

Characteristics of a birefringence compensation scheme in nd3+ : Yag rods using a polarization rotator and imaging optics

A numerical model based on ray optics formulation taking the optical path length into account was described and applied to numerical investigations on a thermal birefringence compensation scheme proposed and experimentally demonstrated by Q, Lüet al. [Opt. Quantum Electron.28 (1996) 57]. Taking into consideration the thermal lensing effects of laser rods depolarization losses and spatial intensity profiles of depolarized beams were calculated for the scheme. It was theoretically confirmed that using a polarization rotator and imaging optics effective compensation for the birefringence in rods is possible for a wide range of pumping power.     

Non-Gaussianity of Racetrack Inflation Models

In this paper, we use the result in [C.Y. Sun and D.H. Zhang, arXivastro-ph/0510709] to calculate the non-Gaussianity of the racetrack models in[J.J. Blanco-Pillado, et al., JHEP 0411 (2004) 063; arXivhep-th/0406230]and [J.J. Blanco-Pillado, et al., arXivhep-th/0603129]. The two models give different non-Gaussianities. Both of them are reasonable. However, we find that, for multi-field inflationary models with the non-trivial metric of the field space,the condition of the slow-roll cannot guarantee small non-Gaussianities.     

Enhanced Multiparty Controlled QSDC Using GHZ State

Recently, Gao et al. [Opt. Commun. 283 (2010) 192] pointed out that Wang et al.'s multiparty controlled quantum secure directcommunication (CQSDC) protocol [Opt. Commun. 266 (2006)732] has the information leakage problem and proposed an improvedprotocol. However, in the improved protocol, due to the introductionof an additional random sampling to avoid the weakness, the qubitefficiency is decreased. By introducing the base changing techniqueto the random sampling in Wang et al.'s protocol, this study overcomesthe information leakage problem and provides a better qubit efficiency.     

Non-Gaussianity of Racetrack Inflation Models

In this paper, we use the result in [C.Y. Sun and D.H. Zhang, arXiv:astro-ph/0510709] to calculate the non-Gaussianity of the racetrack models in [J.J. Blanco-Pillado, et al., JHEP 0411 (2004) 063; arXiv:hep-th/0406230] and [J.J. Blanco-Pillado, et al., arXiv:hep-th/0603129]. The two models give different non-Gaussianities. Both of them are reasonable. However, we find that, for multi-field inflationary models with the non-trivial metric of the field space, the condition of the slow-roll cannot guarantee small non-Gaussianities.     

氖,硅和钛元素的类锂离子激发态参数的计算

为利用本所重离子加速器原子物理实验装置进行高电离态离子物理实验研究，本文采用郑能武等人＾［＾１＾］提出的最弱受约束电子势模型理论的波函数和Ｈ．Ａ．Ｂｅｔｈｅ等入＾［＾２＾］的量子力学理论，估算了Ｎｅ，Ｓｉ和Ｔｉ离子的类锂等电子序２Ｓ－２Ｐ态的跃迁几率和振子强度，并把计算结果与文献结果作了比较。     

Comment on "microstructured polymer fiber laser"

We comment on the recent Letter by Argyros et al. [Opt. Lett. 29, 1882 (2004)] in which a microstructured polymer fiber doped with the dye Rhodamine 6G was discussed as a possible fiber laser source. We suggest that the lasing action at 632 nm was due to stimulated Raman scattering in the poly(methyl methacrylate) host material.     

Fast calculation technique for scattering in T-matrix method

In scattering calculations using the T-matrix method, the calculation of the T-matrix involves multiplication and inversion of matrices. These two types of matrix operations are time-consuming, especially for the matrices with large size. Petrov et al. [D. Petrov, Y. Shkuratov, G. Videen, Opt. Lett. 32 (2007) 1168] proposed an optimized matrix inversion technique, which suggests the inversion of two matrices, each of which contains half the number of rows. This technique reduces time-consumption significantly. On the basis of this approach, we propose another fast calculation technique for scattering in the T-matrix method, which obtains the scattered fields through carrying out only the operations between matrices and the incident field coefficient. Numerical results show that this technique can decrease time-consumption by more than half that of the optimized matrix inversion technique by Petrov et al.     

Cryptanalysis of multiparty quantum secret sharing with collective eavesdropping-check

In the paper [S. Lin, Q.Y. Wen, S.J. Qin, F.C. Zhu, Opt. Commun. 282 (2009) 4455], Lin et al. put forward a quantum secret sharing protocol in which the collective eavesdropping-check is employed. We study the security of this protocol and find that it is insecure. Two dishonest agents may collaborate to eavesdrop (half of) Alice's secret messages without introducing any error.