In Memoriam

In 1905 Lord Kelvin (1824–1907) was awarded the second John Fritz Medal for a lifetime of outstanding achievements in science and technology. I sketch Kelvin’s life, education, and work in thermodynamics, electrical technology, and instrumentation, and his role in the laying of the Atlantic cable. I then turn to Kelvin’s four visits to America, in 1876 on the centenary of the Declaration of Independence of the United States of America; in 1884 when he gave his famous Baltimore Lectures at The Johns Hopkins University; in 1897 when he visited Niagara Falls for the third time and advised George Westinghouse (1846–1914) on how to develop its enormous water power for the generation of electricity; and in 1902 when he advised George Eastman (1854–1932) on the development of the photographic industry. Written in connection with the Kelvin Centenary Year 2007; see “Celebrating the Life of Lord Kelvin,” University of Glasgow News Review No. 11 (2007), 4. Matthew Trainer: Matthew Trainer received his M.Phil. degree in physical sciences at the University of Edinburgh in 1980 and currently is a laboratory instructor at the University of Glasgow where his research focuses in part on the life and work of Lord Kelvin.     

The Physical Tourist

I provide a tour of Madrid, focusing especially on physical institutions that were created during the 19th and 20th centuries.These include the Astronomical Observatory close to the Prado Museum, which itself was conceived as a home for the Royal Academy of Sciences but became instead a world-famous art museum in 1819, leaving the Royal Academy of Sciences without a permanent home until 1866.The Laboratory of Physical Researches was created in 1910, and under the direction of Blas Cabrera (1878–1945), who also held a professorship at the Universidad Central, it fostered most of the Spanish research in physics at the time, in particular the famous spectroscopic researches of Miguel A. Catalán (1894–1957). Nearby were the so-called Transatlantico building and the Students’ Residence where Albert Einstein (1879–1955), for example, lectured in 1923, and which together continue to serve as a major cultural center in Madrid. Later, the physical laboratory was replaced by the National Institute of Physics and Chemistry, which was constructed with funds from the Rockefeller Foundation and inaugurated in 1932. A new University City with its Faculty of Sciences also was constructed on the northwestern outskirts of Madrid, but almost all of its buildings were totally destroyed during the devastating Spanish Civil War of 1936–1939. It was reconstructed after the war and became home, for example, to Spain’s first nuclear reactor, which achieved criticality in 1958.     

A higher order lattice BGK model for simulating some nonlinear partial differential equations

In this paper, we consider a one-dimensional nonlinear partial differential equation that has the form ut + αuux + βunux - γuxx + δuxxx = F(u). A higher order lattice Bhatnager-Gross-Krook (BGK) model with an amending-function is proposed. With the Chapman-Enskog expansion, different kinds of nonlinear partial differential equations are recovered correctly from the continuous Boltzmann equation. The numerical results show that this method is very effective.     

Energy of scattering solitons in the Ward model

We present the results derived in our paper [Proc. Royal. Soc. Lond. A 461 (2005) 1965], where we have shown that the energy density of a scattering-soliton solution in Ward's integrable chiral model is the same as the energy density of a static multi-lump solution of the ℂP ³ sigma model. This explains the quantization of the total energy in the Ward model. Presented at the International Colloquium “Integrable Systems and Quantum Symmetries”, Prague, 16–18 June 2005.     

Interpretations of Quantum Mechanics in Terms of Beable Algebras

In terms of beable algebras Halvorson and Clifton [International Journal of Theoretical Physics 38 (1999) 2441–2484] generalized the uniqueness theorem (Studies in History and Philosophy of Modern Physics 27 (1996) 181–219] which characterizes interpretations of quantum mechanics by preferred observables. We examine whether dispersion-free states on beable algebras in the generalized uniqueness theorem can be regarded as truth-value assignments in the case where a preferred observable is the set of all spectral projections of a density operator, and in the case where a preferred observable is the set of all spectral projections of the position operator as well.     

Max Born and his legacy to condensed matter physics

After a presentation of Max Born's most salient biographical data, we discuss his contributions to science and science policy, with special emphasis on those related to condensed matter physics. Our discussion includes journal articles as well as books. The methodology used is both qualitative and quantitative, including number of items, number of formal and informal citations, and other bibliometric indicators such as the recently proposed Hirsch index (h‐index). The data are mainly based on the Thomson/ISI Web of Science (WoS) which covers a carefully selected set of the more prestigious journals dating back to 1900. Born's books and articles not published in the journals covered by the WoS can also be evaluated, provided they are cited within the WoS journals. Some anecdotic and historical details, which have come to the fore in the course of our bibliometric investigations, are included.     

On the Truncation of Systems with Non-Summable Interactions

In this note we consider long-range q-states Potts models on Z ^d , d≥ 2. For various families of non-summable ferromagnetic pair potentials φ(x)≥ 0, we show that there exists, for all inverse temperature β > 0, an integer N such that the truncated model, in which all interactions between spins at distance larger than N are suppressed, has at least q distinct infinite-volume Gibbs states. This holds, in particular, for all potentials whose asymptotic behaviour is of the type φ(x)∼ ‖x‖^−α, 0≤α≤ d. These results are obtained using simple percolation arguments. Work supported by Swiss National Foundation for Science, Conselho Nacional de Desenvolvimento Cientìfico e Tecnològico, and Programa de Auxìlio para Recèm Doutores PRPq-UFMG.     

Threshold proxy quantum signature scheme with threshold shared verification

A threshold proxy quantum signature scheme with threshold shared verification is proposed. An original signer could authorize a group as its proxy signers. Then only t or more of n persons in the proxy group can generate the proxy signature on behalf of the original signer and any t − 1 or fewer ones cannot do that. When the proxy signature needs to be verified, any t or more of n persons belonging to the verification group can verify the message and any t − 1 or fewer ones cannot verify the validity of the proxy signature. Supported by the National Basic Research Program of China (973 Program)(Grant No. 2007CB311100), the National High-Technology Research and Development Program of China (Grant Nos. 2006AA01Z419 and 20060101Z4015), the Major Research Plan of the National Natural Science Foundation of China (Grant No. 90604023), the Scientific Research Common Program of Beijing Municipal Commission of Education (Grant No. KM200810005004), the Scientific Research Foundation for the Youth of Beijing University of Technology (Grant No. 97007016200701), the Doctoral Scientific Research Activation Foundation of Beijing University of Technology (Grant No. 52007016200702), and the National Laboratory for Modern Communications Science Foundation of China (Grant No. 9140C1101010601)     

Experimental study on the local similarity scaling of the turbulence spectrum in the turbulent boundary layer

The streamwise fluctuating velocity in the turbulent boundary layer is measured under approximately medium Reynolds Number by hot wire in order to investigate the scaling properties of the overlapped turbulent spectrum among energy-containing area, inertial subrange and dissipation range based on FFT analysis. The experiment indicates that the high Reynolds flow reported before is not indispensable to produce −1 scaling. So far as the measured position is provided with much higher spatial resolution and enough closing to the wall, −1 scaling is determinate to exist when approaching medium Reynolds. The scaling ranges are supposed to begin at inner scale and end in outer scale, which reveals the local similarity of the energy spectrum over the energy-containing eddies near the wall. In the logarithmic area (y ⁺ > 130), −5/3 scaling occurs in the energy spectrum, while moving away from the wall with Reynolds numbers increasing, the inertial subrange extends to the lower wavenumbers. On the condition k ₁ η ≫ 0.1, the curves of the turbulence spectrum in the logarithmic layer are superposed, which expresses the similarity of turbulence energy distributed in Komogorov scaling area and exhibits local isotropy characteristics by virtue of the viscous dissipation. Supported by the National Natural Science Foundation of China (Grant Nos. 10832001 and 10872145), the Program for New Century Excellent Talents in Universities of Education Ministry of China, and the Plan of Tianjin Science and Technology Development (Grant No. 06TXTJJC13800)     

Longitudinal study on patent citations to academic research articles in nanotechnology (1976–2004)

Academic nanoscale science and engineering (NSE) research provides a foundation for nanotechnology innovation reflected in patents. About 60% or about 50,000 of the NSE-related patents identified by “full-text” keyword searching between 1976 and 2004 at the United States Patent and Trademark Office (USPTO) have an average of approximately 18 academic citations. The most cited academic journals, individual researchers, and research articles have been evaluated as sources of technology innovation in the NSE area over the 28-year period. Each of the most influential articles was cited about 90 times on the average, while the most influential author was cited more than 700 times by the NSE-related patents. Thirteen mainstream journals accounted for about 20% of all citations. Science, Nature and Proceedings of the National Academy of Sciences (PNAS) have consistently been the top three most cited journals, with each article being cited three times on average. There is another kind of influential journals, represented by Biosystems and Origin of Life, which have very few articles cited but with exceptionally high frequencies. The number of academic citations per year from ten most cited journals has increased by over 17 times in the interval (1990–1999) as compared to (1976–1989), and again over 3 times in the interval (2000–2004) as compared to (1990–1999). This is an indication of increased used of academic knowledge creation in the NSE-related patents.     

High resolution measurement of bragg cut-off in beryllium

Bragg cut-off for plane of polycrystalline beryllium of various lengths of 300 and 116 K has been measured with an energy resolution of 5 μeV. The natural width of the cut-off is 12.5±1.5 μeV, independent of temperature and length of beryllium and also of physical characteristics and certain metallurgical treatments of the powder. Such blocks of beryllium would be suitable for designing a ΔT-window spectrometer with resolution ⩾20 μeV. Bragg cut-offs corresponding to (0002) and planes of beryllium have been separated for the first time. These can also be used for producing additional energy windows in a ΔT-window spectrometer, thus increasing its efficiency. Paper entitled ‘ΔT-window spectrometer’ will appear in the November issue of Pramana.     

The high-pressure <Emphasis Type="Bold">α/β</Emphasis> phase transition in lead sulphide (PbS)

The high-pressure behaviour of PbS was investigated by angular dispersive X-ray powder diffraction up to pressures of 6.8 GPa. Experiments were accompanied by first principles calculations at the density functional theory level. By combining both methods reliable data for the elastic properties of rock-salt type α- and high-pressure β-PbS could be obtained. β-PbS could be determined to crystallise in the CrB-type (B33), with space group Cmcm. The reversible ferro-elastic α/β transition is of first order. It is accompanied by a large volume discontinuity of about 5% and a coexistence region of the two phases. A gliding mechanism of {001} bilayers along one of the cubic 〈110〉 directions governs the phase transition which can be described in terms of group/subgroup relationships via a common subgroup, despite its reconstructive character. The quadrupling of the primitive unit cell indicates a wave vector (0, 0,π/ a ) on the Δ-line of the Brillouin zone. Received 11 October 2002 Published online 14 February 2003 RID="a" ID="a"Also at: Institute of Physics of the Czech Academy of Sciences, Cukrovarnicka 10, 16253 Praha 6, Czech Republic e-mail: knorr@min.uni-kiel.de RID="b" ID="b"Present address: University of Cambridge, Cavendish Laboratory (TCM), Madingley Road, Cambridge CB3 0HE, UK RID="c" ID="c"Present address: Johann-Wolfgang Goethe Universit?t, Mineralogisches Institut, Kristallographie, Senckenberganlage 30, D 60054 Frankfurt a.M., Germany     

Interference of two Bose-Einstein condensates

The visibility of the density interference pattern of two Bose-Einstein condensates, which are produced in traps and overlap after the trapping potential is switched off, is investigated. Coherent wave packets are used to describe the order parameter in a second-quantization formalism. This results in a decrease of the visibility of the interference fringes with increasing time delay between the formation of the condensates and the observation of interference. In the two limiting cases of ideal and very dense gases the correlation time increases, τ→∞, and the result is identical to that obtained using an approach based on the Gross-Pitaevskii equation. Under the conditions of the experiment performed by M. R. Andrews, C. G. Townsend, H. J. Miesner et al., Science 275, 6367 (1997), the computed correlation time τ≈0.2 s is much longer than the confinement time of the condensate, and it is possible to observe the predicted decrease of visibility of the interference fringes of the density of the atoms. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 7, 491–496 (10 April 1999)     

Generalized two-mode coherent-entangled state with real parameters

The coherent-entangled state |α, x; λ> with real parameters λ is proposed in the two-mode Fock space, which exhibits the properties of both the coherent and entangled states. The completeness relation of |α, x; λ> is proved by virtue of the technique of integral within an ordered product of operators. The corresponding squeezing operator is derived, with its own squeezing properties. Furthermore, generalized P-representation in the coherent-entangled state is constructed. Finally, it is revealed that superp...     

Berkeley and Its Physics Heritage

I first sketch the settlement of Berkeley, California, the founding of the University of California at Berkeley, and the origin of its Department of Physics. I then discuss the pivotal role that Ernest O. Lawrence (1901–1958) and his invention and subsequent development of the cyclotron played in physics at Berkeley after his arrival there in 1928 through the Second World War and beyond. I close by commenting on the Lawrence Hall of Science, the educational center and science museum conceived as a living memorial to Lawrence.     

Spectral Analysis for Systems of Atoms and Molecules Coupled to the Quantized Radiation Field

We consider systems of static nuclei and electrons – atoms and molecules – coupled to the quantized radiation field. The interactions between electrons and the soft modes of the quantized electromagnetic field are described by minimal coupling, p→p−e A (x), where A(x) is the electromagnetic vector potential with an ultraviolet cutoff. If the interactions between the electrons and the quantized radiation field are turned off, the atom or molecule is assumed to have at least one bound state. We prove that, for sufficiently small values of the fine structure constant α, the interacting system has a ground state corresponding to the bottom of its energy spectrum. For an atom, we prove that its excited states above the ground state turn into metastable states whose life-times we estimate. Furthermore the energy spectrum is absolutely continuous, except, perhaps, in a small interval above the ground state energy and around the threshold energies of the atom or molecule. Received: 3 September 1998 / Accepted: 17 March 1999     

An improved model for band tail states inn-type degenerate semiconductors

Summary Using two screened donor potential energy models and a wave vectork-positionr uncertainty relation, the results of the exponential band tail states, inn-type degenerate semiconductors, obtained in our previous paper, are improved. The second-order cumulant or the correlation functionW (ϱ,E) is expressed as a function of the total donor concentration ϱ and total carrier energyE. Near band edges, the conduction and valence band tails are, respectively, proportional to exp [E/E ₀(ϱ)] and exp [−E/E ₀(ϱ)], whereE ₀(ϱ) is the energy characteristic of the appropriate band tail, in good accordance with those experimentally obtained by Pankove. Far below the conduction band edge, our result of the conduction band tail is proportional to exp [−BE ² exp [A ]], whereA andB are the functions of ϱ, which is reduced to zero more rapidly in comparison with the corresponding result obtained by Halperin and Lax (i.e. exp [−|E| ⁿ , wheren varies between 1/2 and 2). To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

"Positronic" effective charges of anions in polar substances

The "positronic" effective charges of anions in polar substances are investigated further on the basis of the optical — positron model proposed in 1966 by Gol’danskii and Prokop’ev [Fiz. Tverd. Tela,8, No. 2, 515 (1966)] and developed in 1990 by Aref’ev and Prokof’ev [Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, 52 (1990)] (modified optical model). High productivity of this model in determining anion effective charges in various polar substances (ionic crystals, semiconductors with ionic chemical bonds, etc.) is demonstrated. A. Yu. Malinin Scientific Research Institute for Materials Science. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 23–29, February, 1997.     

Large-scale amplification of a magnetic field by turbulent helicity fluctuations

In this paper the procedure of large-scale averaging of the magnetic-field diffusion equation with the α-term curlα(r,t)B(r,t) is used to show that a nonuniform distribution of the turbulent helicity fluctuations (more precisely, the fluctuations of the coefficient α) with a zero average value gives rise to large-scale amplification of the initial magnetic field. A detailed study is carried out of the dependence of the resulting large-scale α effect on the characteristics of the correlator 〈〈α(r, t)α(r″,t″)〉〉 in a rotating medium with a nonuniform distribution of the angular velocity ω=ω(ρ,z) (ρ is the distance for the rotation axis z). The effect of helicity fluctuations and the diffusion coefficient on the turbulent diffusion process is also investigated. Zh. éksp. Teor. Fiz. 116, 85–104 (July 1999)