Directly observing squeezed phonon states with femtosecond x-ray diffraction

Squeezed states are quantum states of a harmonic oscillator in which the variance of two conjugate variables each oscillate out of phase. Ultrafast optical excitation of crystals can create squeezed phonon states, where the variance of the atomic displacements oscillates due to a sudden change in the interatomic bonding strength. With femtosecond x-ray diffraction we measure squeezing oscillations in bismuth and conclude that they are consistent with a model in which electronic excitation softens all phonon modes by a constant scaling factor

Ultrafast changes in lattice symmetry probed by coherent phonons

The electronic and structural properties of a material are strongly determined by its symmetry. Changing the symmetry via a photoinduced phase transition offers new ways to manipulate material properties on ultrafast timescales. However, in order to identify when and how fast these phase transitions occur, methods that can probe the symmetry change in the time domain are required. We show that a time-dependent change in the coherent phonon spectrum can probe a change in symmetry of the lattice potential, thus providing an all-optical probe of structural transitions. We examine the photoinduced structural phase transition in VO2 and show that, above the phase transition threshold, photoexcitation completely changes the lattice potential on an ultrafast timescale. The loss of the equilibrium-phase phonon modes occurs promptly, indicating a non-thermal pathway for the photoinduced phase transition, where a strong perturbation to the lattice potential changes its symmetry before ionic rearrangement has occurred.Comment: 14 pages 4 figure

Time resolved pattern evolution in a large aperture laser

We have measured quasi-instantaneous transverse patterns in a broad aperture laser. Non-ordered patterns yielding to boundary determined regular structures in progressive time-integrated recording are observed. The linear analysis and numerical integration of the full Maxwell-Bloch equations allow us to interpret the features of the experiment. We show that this system being far from threshold cannot be fully understood with a perturbative model.Comment: 7 pages, 5 GIF figures . To be published in Phys. Rev. Let

Restoring interlayer Josephson coupling in La1.885Ba0.115CuO4 by charge transfer melting of stripe order

We show that disruption of charge-density-wave (stripe) order by charge transfer excitation, enhances the superconducting phase rigidity in La1.885Ba0.115CuO4. Time-resolved resonant soft x-ray diffraction demonstrates that charge order melting is prompt following near-infrared photoexcitation whereas the crystal structure remains intact for moderate fluences. THz time-domain spectroscopy reveals that, for the first 2 ps following photoexcitation, a new Josephson plasma resonance edge, at higher frequency with respect to the equilibrium edge, is induced indicating enhanced superconducting interlayer coupling. The fluence dependence of the charge-order melting and the enhanced superconducting interlayer coupling are correlated with a saturation limit of ∼0.5mJ/cm2. Using a combination of x-ray and optical spectroscopies we establish a hierarchy of timescales between enhanced superconductivity, melting of charge order, and rearrangement of the crystal structure

The Personality of Sugihara Chiune (1900–1986) and the Preservation of Historical Memory of Him After World War II

The article is dedicated to researching the biography and historical memory of the Japanese consul in Lithuania in 1939–1940 and the only Japanese Righteous Among the Nations Sugihara Chiune, who issued 2139 transit visas to Polish and Lithuanian Jews from July to September 1940, which helped them escape the tragedy of the Holocaust in Lithuania after the German attack on the USSR.For the reader’s convenience, the work is divided into 5 parts. The first focuses on the stages of Sugihara’s career before his appointment as consul in Kaunas: his early biography (1900–1919), his study of Russian in Harbin (1919–1924), his work at the Japanese Consulate General (1925–1932) and the Manchukuo Foreign Ministry (1932–1935), his transfer to the Japanese Foreign Ministry in Tokyo (1935–1937), and his departure for a diplomatic mission in Finland (1937–1939). Along with a description of his professional development, an important place in this part is occupied by an analysis of Sugihara’s personal life and the process of shaping his views, which subsequently determined his willingness to act in a way that, at first glance, was not typical of a diplomat of militarist Japan.The second and third parts describe Sugihara’s activities in Kaunas (1939– 1940). Attention is paid both to his intelligence activities with the support of Polish agents and to his private life, the events of which developed Sugihara’s earlier capacity for sympathy for people of other nationalities. It also details the process of issuing transit visas to Jewish refugees, deliberately carried out in violation of Foreign Ministry instructions, as well as estimates of the number who left Lithuania thanks to Sugihara and describes their further journey.The fourth part, although small, covers a broad period in the life of the former Japanese consul in Lithuania: his work in Prague (1940–1941), Königsberg (1941), and Bucharest (1941–1944), internment and repatriation to Japan (1944–1947), work in various commercial firms (1947–1975) and the process of recognition as a Righteous (1984).Finally, the final part of the paper is devoted to the analysis of the historical memory of Sugihara in Israel, Japan, the USA, Poland, Lithuania, and Russia, as well as identification of the main differences in its nature and the reasons that determined this heterogeneity

Between the Eurasian and European subsystems: migration and migration policy in the CIS and Baltic Countries in the 1990s - 2020s

The article analyses migration from border countries (the so-called overlapping area) of two migration subsystems - Eurasian (centred in the Russian Federation) and European (the European Union) from 1991 to 2021 (before the recent events in Ukraine). A step-by-step analysis of the migration situation in the countries of the former USSR - Belarus, Latvia, Lithuania, Moldova, Ukraine and Estonia was conducted. The article examines bilateral and multilateral migration processes, analyses the main factors influencing their development and explores migration policy measures and their impact on the regulation of migration processes in the countries of the overlapping area. These countries, located between the two centres of major migration subsystems in Eurasia (Eurasian and European, or, in other words, between the Russian Federation and the core of the EU), are subject to their strong influence and 'competitive gravitation'. The strength of this gravitation depends not only on pull and push factors but also on the attractiveness and non-attractiveness of the migration policies prevailing in these migration subsystems at a given point in time

EPR detection of presumable quantum behavior of iron oxide nanoparticles in dendrimeric nanocomposite

© 2017 Elsevier B.V.The superparamagnetic γ-Fe2O3 nanoparticles (average diameter of 2.5 nm) encapsulated in poly(propylene imine) dendrimer have been investigated by Electron Magnetic Resonance (EMR). EMR measurements have been recorded in perpendicular and parallel configurations in the wide temperature range (4.2–300 K). It has been shown that the model based on the spin value S = 30, corresponding to the total magnetic moment of the nanoparticle, can be used to interpret the experimental results and the proof of the quantum behavior of γ-Fe2O3 nanoparticles

Parameters of communication behavior and national language

Analyze the category of "language behavior" in modern linguistic research. It states provisions of the communicative interpretation of the logical-semantic structure of utterances to determine their ethnocultural feature

Directly Observing Squeezed Phonon States with Femtosecond X-Ray Diffraction

Squeezed states are quantum states of a harmonic oscillator in which the variance of two conjugate variables each oscillate out of phase. Ultrafast optical excitation of crystals can create squeezed phonon states, where the variance of the atomic displacements oscillates due to a sudden change in the interatomic bonding strength. With femtosecond x-ray diffraction we measure squeezing oscillations in bismuth and conclude that they are consistent with a model in which electronic excitation softens all phonon modes by a constant scaling factor