2,088 research outputs found
Theory of Quark-Gluon Plasma and Phase Transition
Nonperturbative picture of strong interacting quark-gluon plasma is given
based on the systematic Field Correlator Method. Equation of state, phase
transition in density-temperature plane is derived and compared to lattice data
as well as subsequent thermodynamical quantities of QGP.Comment: 6 pages,5 figures; talk given at "13th Lomonosov Conference on
Elementary Particle Physics", Moscow, August 23 -- 29, 2007; new reference
adde
On integration of the Kowalevski gyrostat and the Clebsch problems
For the Kowalevski gyrostat change of variables similar to that of the
Kowalevski top is done. We establish one to one correspondence between the
Kowalevski gyrostat and the Clebsch system and demonstrate that Kowalevski
variables for the gyrostat practically coincide with elliptic coordinates on
sphere for the Clebsch case. Equivalence of considered integrable systems
allows to construct two Lax matrices for the gyrostat using known rational and
elliptic Lax matrices for the Clebsch model. Associated with these matrices
solutions of the Clebsch system and, therefore, of the Kowalevski gyrostat
problem are discussed. The Kotter solution of the Clebsch system in modern
notation is presented in detail.Comment: LaTeX, 24 page
Intelligent OFDM telecommunication system. Part 3. Anti-eavesdropping and anti-jamming properties of system, based on many-parameter wavelet and Golay transforms
In this paper, we aim to investigate the superiority and practicability of many-parameter Fourier transforms (MPFT) from the physical layer security (PHY-LS) perspective. We propose novel Intelligent OFDM-telecommunication system (Intelligent-OFDM-TCS), based on MPFT. New system uses inverse MPFT for modulation at the transmitter and direct MPFT for demodulation at the receiver. The purpose of employing the MPFTs is to improve the PHY-LS of wireless transmissions against to the wide-band anti-jamming communication. Each MPFT depends on finite set of independent parameters (angles), which could be changed independently one from another. When parameters are changed, multi-parametric transform is also changed taking form of a set known (and unknown) orthogonal (or unitary) transforms. We implement the following performances as bit error rate (BER), symbol error rate (SER), the Shannon-Wyner secrecy capacity (SWSC) for novel Intelligent-MPWT-OFDM-TCS. Previous research has shown that the conventional OFDM TCS based on discrete Fourier transform (DFT) has unsatisfactory characteristics in BER, SWSC and in anti-eavesdropping communications. We study Intelligent-MPWT-OFDM-TCS to find out optimal values of angle parameters of MPFT optimized BER, SWSC, anti-eavesdropping effects. Simulation results show that the proposed Intelligent OFDM-TCS have better performances than the conventional OFDM system based on DFT against eavesdropping. Β© 2019 IOP Publishing Ltd. All rights reserved
Quantum tops as examples of commuting differential operators
We study the quantum analogs of tops on Lie algebras and
represented by differential operators.Comment: 24 p
Many factor mimo-filters
ΠΡΡΠ»Π΅Π΄ΡΠ΅ΡΡΡ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΠΌΠΎΠ΄ΠΈΡΠΈΡΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΠΌΠ½ΠΎΠ³ΠΎΡΠ°ΠΊΡΠΎΡΠ½ΡΡ
(Π±ΠΈ-, ΡΡΠΈ- ΠΈ ΡΠ΅ΡΡΡΠ΅Ρ
-Π»Π°ΡΠ΅ΡΠ°Π»ΡΠ½ΡΡ
) MIMO-ΡΠΈΠ»ΡΡΡΠΎΠ² Π΄Π»Ρ ΡΠ΅ΡΡΡ
, ΡΠ²Π΅ΡΠ½ΡΡ
ΠΈ Π³ΠΈΠΏΠ΅ΡΡΠΏΠ΅ΠΊΡΡΠ°Π»ΡΠ½ΡΡ
ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΠΉ. ΠΠ±ΡΡΠ½ΡΠ΅ Π±ΠΈΠ»Π°ΡΠ΅ΡΠ°Π»ΡΠ½ΡΠ΅ ΡΠΈΠ»ΡΡΡΡ ΠΎΡΡΡΠ΅ΡΡΠ²Π»ΡΡΡ Π²Π·Π²Π΅ΡΠ΅Π½Π½ΠΎΠ΅ ΡΡΡΠ΅Π΄Π½Π΅Π½ΠΈΠ΅ ΡΠΎΡΠ΅Π΄Π½ΠΈΡ
ΠΏΠΈΠΊΡΠ΅Π»Π΅ΠΉ. ΠΠ΅ΡΠ° Π²ΠΊΠ»ΡΡΠ°ΡΡ Π΄Π²Π΅ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΡ: ΠΏΡΠΎΡΡΡΠ°Π½ΡΡΠ²Π΅Π½Π½ΡΡ ΠΈ ΡΠ°Π΄ΠΈΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΡΡ. ΠΠ΅ΡΠ²Π°Ρ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΠ° ΡΡΠΈΡΡΠ²Π°Π΅Ρ Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠ΅ ΠΌΠ΅ΠΆΠ΄Ρ ΡΠ΅Π½ΡΡΠ°Π»ΡΠ½ΡΠΌ ΠΏΠΈΠΊΡΠ΅Π»Π΅ΠΌ ΠΌΠ°ΡΠΊΠΈ ΠΈ Π΅Π³ΠΎ Π»ΠΎΠΊΠ°Π»ΡΠ½ΡΠΌΠΈ ΡΠΎΡΠ΅Π΄ΡΠΌΠΈ. ΠΡΠΎΡΠΎΠΉ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½Ρ ΡΡΠΈΡΡΠ²Π°Π΅Ρ ΡΠ°Π΄ΠΈΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠ΅ ΠΌΠ΅ΠΆΠ΄Ρ ΡΠ΅Π½ΡΡΠ°Π»ΡΠ½ΡΠΌ ΠΏΠΈΠΊΡΠ΅Π»Π΅ΠΌ ΠΌΠ°ΡΠΊΠΈ ΠΈ Π΅Π³ΠΎ Π»ΠΎΠΊΠ°Π»ΡΠ½ΡΠΌΠΈ ΡΠΎΡΠ΅Π΄ΡΠΌΠΈ. Π ΡΡΠΎΠΌ ΠΊΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΌ Π°Π»Π³ΠΎΡΠΈΡΠΌΠ΅ ΡΠ΅Π½ΡΡΠ°Π»ΡΠ½ΡΠΉ ΠΏΠΈΠΊΡΠ΅Π»Ρ ΠΌΠ°ΡΠΊΠΈ ΠΈΠ³ΡΠ°Π΅Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΡΡΡΡ ΡΠΎΠ»Ρ Π² ΠΊΠΎΠ½Π΅ΡΠ½ΠΎΠΌ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ΅ ΡΠΈΠ»ΡΡΡΠ°ΡΠΈΠΈ. ΠΡΠ»ΠΈ ΠΎΠ½ ΠΈΡΠΊΠ°ΠΆΠ΅Π½, ΡΠΎ ΠΈ ΡΠ΅Π·ΡΠ»ΡΡΠ°Ρ ΡΠΈΠ»ΡΡΡΠ°ΡΠΈΠΈ Π±ΡΠ΄Π΅Ρ ΠΈΡΠΊΠ°ΠΆΠ΅Π½Π½ΡΠΌ. ΠΡΠΎΡ ΡΠ°ΠΊΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅Ρ ΠΏΠ΅ΡΠ²ΡΡ ΠΌΠΎΠ΄ΠΈΡΠΈΠΊΠ°ΡΠΈΡ: ΡΠ΅Π½ΡΡΠ°Π»ΡΠ½ΡΠΉ ΠΏΠΈΠΊΡΠ΅Π»Ρ Π·Π°ΠΌΠ΅Π½ΡΠ΅ΡΡΡ Π΅Π³ΠΎ Π»ΡΠ±ΠΎΠΉ ΡΠ³Π»Π°ΠΆΠ΅Π½Π½ΠΎΠΉ Π²Π΅ΡΡΠΈΠ΅ΠΉ, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΠΎΠΉ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΡΠΎΡΠ΅Π΄Π½ΠΈΡ
ΠΏΠΈΠΊΡΠ΅Π»Π΅ΠΉ. ΠΡΠΎΡΠ°Ρ ΠΌΠΎΠ΄ΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅Ρ ΠΌΠ°ΡΡΠΈΡΠ½ΠΎ-Π·Π½Π°ΡΠ½ΡΠ΅ Π²Π΅ΡΠ°. ΠΠ½ΠΈ Π²ΠΊΠ»ΡΡΠ°ΡΡ ΡΠ΅ΡΡΡΠ΅ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΡ: ΠΏΡΠΎΡΡΡΠ°Π½ΡΡΠ²Π΅Π½Π½ΡΡ, ΡΠ°Π΄ΠΈΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΡΡ, ΠΌΠ΅ΠΆΠΊΠ°Π½Π°Π»ΡΠ½ΡΡ ΠΈ ΡΠ°Π΄ΠΈΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΡΡ ΠΌΠ΅ΠΆΠΊΠ°Π½Π°Π»ΡΠ½ΡΡ. Π§Π΅ΡΠ²Π΅ΡΡΡΠΉ Π²Π΅Ρ ΡΡΠΈΡΡΠ²Π°Π΅Ρ ΡΠ°Π΄ΠΈΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠ΅ ΠΌΠ΅ΠΆΠ΄Ρ ΡΠ΅Π½ΡΡΠ°Π»ΡΠ½ΡΠΌ ΠΏΠΈΠΊΡΠ΅Π»Π΅ΠΌ ΠΈ ΠΌΠ΅ΠΆΠΊΠ°Π½Π°Π»ΡΠ½ΡΠΌΠΈ ΡΠΎΡΠ΅Π΄Π½ΠΈΠΌΠΈ ΠΏΠΈΠΊΡΠ΅Π»ΡΠΌΠΈ
FrΓ©chet mimo-filters
ΠΠ΅Π΄ΠΈΠ°Π½Π½Π°Ρ ΡΠΈΠ»ΡΡΡΠ°ΡΠΈΡ ΠΏΠΎΠ»ΡΡΠΈΠ»Π° ΡΠΈΡΠΎΠΊΠΎΠ΅ ΡΠ°ΡΠΏΡΠΎΡΡΡΠ°Π½Π΅Π½ΠΈΠ΅ ΠΏΡΠΈ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠ΅ ΡΠΊΠ°Π»ΡΡΠ½ΡΡ
ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΠΉ Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² ΡΠΈΠ»ΡΡΡΠ°ΡΠΈΠΈ, ΡΠΎΡ
ΡΠ°Π½ΡΡΡΠΈΡ
ΠΏΠ΅ΡΠ΅ΠΏΠ°Π΄Ρ ΡΡΠΊΠΎΡΡΠΈ. ΠΠ»Π°Π²Π½Π°Ρ ΠΈΠ΄Π΅Ρ ΠΌΠ΅Π΄ΠΈΠ°Π½Π½ΠΎΠΉ ΡΠΈΠ»ΡΡΡΠ°ΡΠΈΠΈ ΡΠΎΡΡΠΎΠΈΡ Π² ΡΠΎΠΌ, ΡΡΠΎ ΡΠ΅Π½ΡΡΠ°Π»ΡΠ½ΡΠΉ ΠΏΠΈΠΊΡΠ΅Π»Ρ ΡΠΊΠ°Π½ΠΈΡΡΡΡΠ΅ΠΉ ΠΌΠ°ΡΠΊΠΈ Π·Π°ΠΌΠ΅Π½ΡΠ΅ΡΡΡ ΠΌΠ΅Π΄ΠΈΠ°Π½ΠΎΠΉ Π²ΡΠ΅Ρ
ΠΏΠΈΠΊΡΠ΅Π»Π΅ΠΉ, ΡΠΎΠ΄Π΅ΡΠΆΠ°ΡΠΈΡ
ΡΡ Π² ΠΌΠ°ΡΠΊΠ΅. Π ΡΡΠΎΠΉ ΡΠ°Π±ΠΎΡΠ΅ ΠΈΠ΄Π΅Ρ ΡΠ°ΡΡΠΈΡΡΠ΅ΡΡΡ Π½Π° Π²Π΅ΠΊΡΠΎΡΠ½ΠΎ-Π·Π½Π°ΡΠ½ΡΠ΅ ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΡ. Π Π°ΡΡΠΈΡΠ΅Π½ΠΈΠ΅ ΠΎΡΠ½ΠΎΠ²ΡΠ²Π°Π΅ΡΡΡ Π½Π° ΡΠΎΠΌ ΡΠ°ΠΊΡΠ΅, ΡΡΠΎ ΠΌΠ΅Π΄ΠΈΠ°Π½Π° ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ°ΠΊΠΆΠ΅ ΡΠΎΡΠΊΠΎΠΉ, ΠΊΠΎΡΠΎΡΠ°Ρ ΠΌΠΈΠ½ΠΈΠΌΠΈΠ·ΠΈΡΡΠ΅Ρ ΡΡΠΌΠΌΡ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠΉ ΠΌΠ΅ΠΆΠ΄Ρ Π½Π΅ΠΉ ΠΈ Π²ΡΠ΅ΠΌΠΈ ΡΠΊΠ°Π»ΡΡΠ½ΡΠΌΠΈ ΠΏΠΈΠΊΡΠ΅Π»ΡΠΌΠΈ Π²Π½ΡΡΡΠΈ ΠΌΠ°ΡΠΊΠΈ. Π’ΠΎΡΠΊΠΎΠΉ Π€ΡΠ΅ΡΠ΅ ΠΊΠΎΠ½Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΌΠ½ΠΎΠΆΠ΅ΡΡΠ²Π° Π²Π΅ΠΊΡΠΎΡΠ½ΠΎ-Π·Π½Π°ΡΠ½ΡΡ
ΠΏΠΈΠΊΡΠ΅Π»Π΅ΠΉ Π² Π½Π΅ΠΊΠΎΡΠΎΡΠΎΠΌ ΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΌ ΠΏΡΠΎΡΡΡΠ°Π½ΡΡΠ²Π΅ (Ρ Π·Π°Π΄Π°Π½Π½ΠΎΠΉ ΠΌΠ΅ΡΡΠΈΠΊΠΎΠΉ) ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ°ΠΊΠΎΠΉ Π²Π΅ΠΊΡΠΎΡ, ΡΡΠΌΠΌΠ° ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠΉ Π΄ΠΎ ΠΊΠΎΡΠΎΡΠΎΠ³ΠΎ ΠΎΡ Π²ΡΠ΅Ρ
Π²Π΅ΠΊΡΠΎΡΠ½ΡΡ
ΠΏΠΈΠΊΡΠ΅Π»Π΅ΠΉ (Π½Π°Ρ
ΠΎΠ΄ΡΡΠΈΡ
ΡΡ Π²Π½ΡΡΡΠΈ ΠΌΠ°ΡΠΊΠΈ) ΠΈΠΌΠ΅Π΅Ρ ΠΌΠΈΠ½ΠΈΠΌΠ°Π»ΡΠ½ΠΎΠ΅ Π·Π½Π°ΡΠ΅Π½ΠΈΠ΅. Π Π΄Π°Π½Π½ΠΎΠΉ ΡΡΠ°ΡΡΠ΅ ΠΏΠΎΠ½ΡΡΠΈΠ΅ ΡΠΎΡΠΊΠΈ Π€ΡΠ΅ΡΠ΅ ΡΠ°ΡΡΠΈΡΡΠ΅ΡΡΡ Π΄ΠΎ ΠΎΠ±ΠΎΠ±ΡΠ΅Π½Π½ΠΎΠΉ ΠΌΠ΅Π΄ΠΈΠ°Π½Ρ Π€ΡΠ΅ΡΠ΅, Π² ΠΊΠΎΡΠΎΡΠΎΠΉ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΡΡΡ Π°Π³ΡΠ΅Π³Π°ΡΠΈΡ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠΉ, Π° Π½Π΅ ΠΈΡ
ΡΡΠΌΠΌΠ°. ΠΠΎΠ»Π΅Π΅ ΡΠΎΠ³ΠΎ, ΠΏΡΠΈ ΠΎΠ±ΠΎΠ±ΡΠ΅Π½ΠΈΠΈ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΡΡ Π½Π΅ ΠΊΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΡ, Π° ΠΈΡ
Π°Π³ΡΠ΅Π³Π°ΡΠΈΠΎΠ½Π½ΡΠ΅ ΠΎΠ±ΠΎΠ±ΡΠ΅Π½ΠΈΡ. ΠΠ±ΠΎΠ±ΡΠ΅Π½Π½ΡΠ΅ ΠΌΠ΅Π΄ΠΈΠ°Π½Ρ Π€ΡΠ΅ΡΠ΅ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΡΡ Π΄Π»Ρ ΠΏΠΎΡΡΡΠΎΠ΅Π½ΠΈΡ Π½ΠΎΠ²ΡΡ
ΠΌΠ΅Π΄ΠΈΠ°Π½Π½ΡΡ
MIMO-ΡΠΈΠ»ΡΡΡΠΎΠ²
Multiparametric wavelet transforms
The main goal of the paper is to show that wavelet transforms and packets have the multiparametric representation in the form of a product of the rotation Jacobi matrices. These representations we call the third and the fourth canonical multiparametric form. Each multiparametric wavelet transform (MPWT) depends on several free Jacobi parameters. When parameters are changed multiparametric transform is changed too taking form of all known and unknown orthogonal wavelet transforms. It gives unified approach to describing a wide set of cyclic orthogonal wavelet transforms and endows with adaptive properties of those transforms.ΠΠ»Π°Π²Π½Π°Ρ ΡΠ΅Π»Ρ ΡΡΠ°ΡΡΠΈ β Π²ΡΠ²ΠΎΠ΄ ΠΏΡΠΈΠ½ΡΠΈΠΏΠΈΠ°Π»ΡΠ½ΠΎ Π½ΠΎΠ²ΠΎΠ³ΠΎ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΈΡ Π±ΡΡΡΡΡΡ
ΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΠΈΡ
Π²Π΅ΠΉΠ²Π»Π΅Ρ-ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠΉ Π² Π²ΠΈΠ΄Π΅ ΠΏΡΠΎΠΈΠ·Π²Π΅Π΄Π΅Π½ΠΈΡ ΡΠ»Π°Π±ΠΎΠ·Π°ΠΏΠΎΠ»Π½Π΅Π½Π½ΡΡ
ΠΌΠ°ΡΡΠΈΡ Π²ΡΠ°ΡΠ΅Π½ΠΈΡ, Π·Π°Π²ΠΈΡΡΡΠΈΡ
ΠΎΡ ΠΊΠΎΠ½Π΅ΡΠ½ΠΎΠ³ΠΎ ΡΠΈΡΠ»Π° ΡΠ²ΠΎΠ±ΠΎΠ΄Π½ΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ². ΠΡΠΈ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΌΠ΅Π½ΡΠ΅ΡΡΡ Π²ΠΈΠ΄ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ, ΠΏΡΠΈΠ½ΠΈΠΌΠ°Ρ ΠΎΠ±Π»ΠΈΠΊ ΠΊΠ°ΠΊ Π²ΡΠ΅Ρ
ΠΈΠ·Π²Π΅ΡΡΠ½ΡΡ
, ΡΠ°ΠΊ ΠΈ Π½Π΅ΠΈΠ·Π²Π΅ΡΡΠ½ΡΡ
Π² Π½Π°ΡΡΠΎΡΡΠ΅Π΅ Π²ΡΠ΅ΠΌΡ Π²Π΅ΠΉΠ²Π»Π΅Ρ-ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠΉ ΠΈ Π²Π΅ΠΉΠ²Π»Π΅Ρ-ΠΏΠ°ΠΊΠ΅ΡΠΎΠ², ΡΡΠΎ Π΄Π°Π΅Ρ ΠΏΡΠ°ΠΊΡΠΈΡΠ΅ΡΠΊΡΡ ΠΎΡΠ½ΠΎΠ²Ρ Π΄Π»Ρ ΠΈΡ
ΡΠ½ΠΈΡΠΈΡΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ ΠΎΠΏΠΈΡΠ°Π½ΠΈΡ
On integrable system on with the second integral quartic in the momenta
We consider integrable system on the sphere with an additional integral
of fourth order in the momenta. At the special values of parameters this system
coincides with the Kowalevski-Goryachev-Chaplygin system.Comment: LaTeX, 6 page
Operator method in solving non-linear equations of the Hartree-Fock type
The operator method is used to construct the solutions of the problem of the
polaron in the strong coupling limit and of the helium atom on the basis of the
Hartree-Fock equation. is obtained for the polaron
ground-state energy. Energies for 2s- and 3s-states are also calculated. The
other excited states are briefly discussed.Comment: 7 page
Total spectrum of photon emission by an ultra-relativistic positron channeling in a periodically bent crystal
We present the results of numerical calculations of the channelling and
undulator radiation generated by an ultra-relativistic positron channelling
along a crystal plane, which is periodically bent. The bending might be due
either to the propagation of a transverse acoustic wave through the crystal, or
due to the static strain as it occurs in superlattices. The periodically bent
crystal serves as an undulator. We investigate the dependence of the
intensities of both the ordinary channelling and the undulator radiations on
the parameters of the periodically bent channel with simultaneous account for
the dechannelling effect of the positrons. We demonstrate that there is a range
of parameters in which the undulator radiation dominates over the channelling
one and the characteristic frequencies of both types of radiation are well
separated. This result is important, because the undulator radiation can be
used to create a tunable source of X-ray and gamma-radiation.Comment: published in J. Phys. G: Nucl. Part. Phys. 26 (2000) L87-L95,
http://www.iop.org ; 12 pages, 4 figures, LaTe
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