Properties of KNN ceramics of different phase composition

This work was supported by the Ministry of Education and Science of the Russian Federation and performed at the Collective Usage Center of the Tver State University

Controlling Purity, Indistinguishability and Quantum Yield of Incoherently Pumped Two-Level System by Spectral Filters

Dephasing processes significantly impact the performance of deterministic single-photon sources. Dephasing broadens the spectral line and suppresses the indistinguishability of the emitted photons, which is undesirable for many applications, primarily for quantum computing. We consider a light emitted by a two-level system with a pulsed incoherent pump in the presence of the spectral filter. The spectral filter allows control of the second-order autocorrelation function, indistinguishability, and quantum yield. We show that narrow spectral filters can increase the indistinguishability of the emitted light while undermining the quantum yield. The influence of the spectral filter on the second-order correlation function depends on the duration of the pump. When the pumping pulse is long compared to the lifetime of the two-level system, the narrow spectral filters lead to a rapid increase in the second-order autocorrelation function. In this limit, the statistics of the light from the two-level system inherit the statistics of the incoherent pump. In the case of the short duration of the pump pulse, it is possible to preserve single-photon properties to some degree for the sub-lifetime width of the spectral filter. Moreover, when the light emitted by the single-photon source is used to control a quantum system, e.g., cavity, the single-photon properties of the light manifest themselves differently, depending on the response time of the quantum system. In particular, in the case of long response time, the spectral filter with sub-lifetime width can provide the near-zero second-order autocorrelation function

Synthesis and Characterization of Organic Impurities in Bortezomib Anhydride Produced by a Convergent Technology

A profile of impurities in bortezomib anhydride, produced by a recently developed convergent technology, has been characterized. HPLC-MS analysis of the drug essence revealed three impurities: an epimer of bortezomib, resulting from partial racemization of l-phenylalanine’s stereogenic center during the chemical synthesis, and two epimeric products of oxidative degradation of bortezomib, in which boron is replaced by the OH group. The impurities were obtained by chemical synthesis and characterized by physical methods

Collapses and revivals of polarization and radiation intensity induced by strong exciton-vibron coupling

Recently, systems with strong coupling between electronic and vibrational degrees of freedom attract a great attention. In this work, we consider the transient dynamics of the system consisting of strongly coupled vibron and exciton driven by external monochromatic field. We show that under coherent pumping, polarization of exciton exhibits complex quantum dynamics which can be divided into three stages. At the first stage, exciton oscillations at its eigenfrequency relax due to the transition to set of shifted Fock states of vibrons. We demonstrate that these shifted Fock states play the role of an effective reservoir for the excited exciton state. The time of relaxation to this reservoir depends on exciton-vibron coupling. At the second stage, excitation, transferred to the reservoir of the vibronic shifted states at the first stage, returns into electronic degrees of freedom and revival of oscillations at exciton eigenfrequency appears. Thus, the dynamics of molecular polarization exhibit collapses and revivals. At the final stage, these collapses and revivals dissipate and polarization exhibits Rayleigh response at the frequency of the external field. Discovered collapses and revivals manifest in radiation spectrum as multiple splitting of the spectral line near the exciton transition frequency

Modernization of government management in empires of new time: comparative political analysis

The article deals with the issues related to the modernization of public administration in the imperial states of modern times. Russian, British and Ottoman empires as states implementing various strategies of modernization and improvement of public administration were chosen as examples. The success of modernization reforms of the administration is one of the essential conditions for maintaining stability and development of the imperial political system, formalizing the domination of the center in relation to the periphery. The Ottoman Empire failed to implement the policy of modernization of public administration in a timely and consistent manner. The British Empire was combined the strategies of centralization and decentralization of state management of its overseas colonies. The Russian Empire - a special imperial system -implemented, within the framework of the unitary state, the principle of centralization of the system of management, but its implementation in the development of the central bureaucratic apparatus of the empire was limited by the autocratic monarchy. At the same time, the Russian Empire was flexible in terms of differentiation of the management approaches. The article substantiates the conclusion that the imperial administration was an expression of centripetal political processes in the imperial system provided them and was an expression of the political power of the center which has an autocratic character in relation to the periphery. The processes associated with the administration of the Empire are concentrated in its center and implemented in addition to the will of the periphery. In institutional terms, the center of the empire is represented by general imperial authorities and management, in functional terms, the imperial power has exclusive administrative prerogatives associated with the concentration of resources of power and their distribution over the imperial hierarchy. The differentiation of administrative approaches shows the administrative and political specificity of the empire-state. In general the modernization of management empire became a significant factor in allowing the empire to most effectively carry out the concentration of political resources

Adjoint master equation for multi-time correlators

The quantum regression theorem is a powerful tool for calculating the muli-time correlators of operators of open quantum systems which dynamics can be described in Markovian approximation. It enables to obtain the closed system of equation for the multi-time correlators. However, the scope of the quantum regression theorem is limited by a particular time order of the operators in multi-time correlators and does not include out-of-time-ordered correlators. In this work, we obtain an adjoint master equation for multi-time correlators that is applicable to out-of-time-ordered correlators. We show that this equation can be derived for various approaches to description of the dynamics of open quantum systems, such as the global or local approach. We show that the adjoint master equation for multi-time correlators is self-consistent. Namely, the final equation does not depend on how the operators are grouped inside the correlator, and it coincides with the quantum regression theorem for the particular time ordering of the operators.Comment: 11 page