179 research outputs found
Dipole lasing phase transitions in media with singularities in polarizabilities
We show that a divergence in the optical polarizability of a heterogeneous medium with nonlinear amplification and a strong dipole-dipole interaction between particles can lead to a phase transition, for which the dipole momentum of the particles or the dipole radiation rate can be taken as order parameters. The "dipole laser" (Phys. Rev. A 71, 063812 (2005)) can be used both as a simple example of such a second-order phase transition and to provide a recipe for its analysis. We show that similar phase transitions may be possible for a nanoparticle on the surface of an optically active medium and at the "Clausius-Mossotti" catastrophe in a bulk heterogeneous medium
Dipole nanolaser
A "dipole" laser is proposed consisting of a nanoparticle and a two-level system with population inversion. If the threshold conditions are fulfilled, the dipole interaction between the two-level system and the nanoparticle leads to coherent oscillations in the polarization of the particles, even in the absence of an external electromagnetic field. The emitted radiation has a dipolar distribution. It does not need an optical cavity, and has a very small volume, 0.1 mu m(3), which can be important for applications in microelectronics. Estimates of the threshold conditions are carried out for a dipole laser composed of a quantum dot and a silver nanoparticle
Conditional quantum logic using two atomic qubits
In this paper we propose and analyze a feasible scheme where the detection of
a single scattered photon from two trapped atoms or ions performs a conditional
unitary operation on two qubits. As examples we consider the preparation of all
four Bell states, the reverse operation that is a Bell measurement, and a CNOT
gate. We study the effect of atomic motion and multiple scattering, by
evaluating Bell inequalities violations, and by calculating the CNOT gate
fidelity.Comment: 23 pages, 8 figures in 11 file
Photon polarisation entanglement from distant dipole sources
It is commonly believed that photon polarisation entanglement can only be
obtained via pair creation within the same source or via postselective
measurements on photons that overlapped within their coherence time inside a
linear optics setup. In contrast to this, we show here that polarisation
entanglement can also be produced by distant single photon sources in free
space and without the photons ever having to meet, if the detection of a photon
does not reveal its origin -- the which way information. In the case of two
sources, the entanglement arises under the condition of two emissions in
certain spatial directions and leaves the dipoles in a maximally entangled
state.Comment: 7 pages, 2 figures, revised version, accepted for publication in J.
Phys.
Broadening of Plasmonic Resonance Due to Electron Collisions with Nanoparticle Boundary: Π° Quantum Mechanical Consideration
We present a quantum mechanical approach to calculate broadening of plasmonic
resonances in metallic nanostructures due to collisions of electrons with the
surface of the structure. The approach is applicable if the characteristic size
of the structure is much larger than the de Broglie electron wavelength in the
metal. The approach can be used in studies of plasmonic properties of both
single nanoparticles and arrays of nanoparticles.Comment: 9 page
Comparison of Theory and Experiment for a One-Atom Laser in a Regime of Strong Coupling
Our recent paper reports the experimental realization of a one-atom laser in
a regime of strong coupling (Ref. [1]). Here we provide the supporting
theoretical analysis relevant to the operating regime of our experiment. By way
of a simplified four-state model, we investigate the passage from the domain of
conventional laser theory into the regime of strong coupling for a single
intracavity atom pumped by coherent external fields. The four-state model is
also employed to exhibit the vacuum-Rabi splitting and to calculate the optical
spectrum. We next extend this model to incorporate the relevant Zeeman
hyperfine states as well as a simple description of the pumping processes in
the presence of polarization gradients and atomic motion. This extended model
is employed to make quantitative comparisons with the measurements of Ref. [1]
for the intracavity photon number versus pump strength and for the photon
statistics as expressed by the intensity correlation function g2(tau).Comment: 19 pages, 14 figures. Added sections on: scaling properties,
vacum-Rabi splitting, and optical spectru
Plasmonic atoms and plasmonic molecules
The proposed paradigm of plasmonic atoms and plasmonic molecules allows one
to describe and predict the strongly localized plasmonic oscillations in the
clusters of nanoparticles and some other nanostructures in uniform way.
Strongly localized plasmonic molecules near the contacting surfaces might
become the fundamental elements (by analogy with Lego bricks) for a
construction of fully integrated opto-electronic nanodevices of any complexity
and scale of integration.Comment: 30 pages, 16 figure
Quantum computing in optical microtraps based on the motional states of neutral atoms
We investigate quantum computation with neutral atoms in optical microtraps
where the qubit is implemented in the motional states of the atoms, i.e., in
the two lowest vibrational states of each trap. The quantum gate operation is
performed by adiabatically approaching two traps and allowing tunneling and
cold collisions to take place. We demonstrate the capability of this scheme to
realize a square-root of swap gate, and address the problem of double
occupation and excitation to other unwanted states. We expand the two-particle
wavefunction in an orthonormal basis and analyze quantum correlations
throughout the whole gate process. Fidelity of the gate operation is evaluated
as a function of the degree of adiabaticity in moving the traps. Simulations
are based on rubidium atoms in state-of-the-art optical microtraps with quantum
gate realizations in the few tens of milliseconds duration range.Comment: 11 pages, 7 figures, for animations of the gate operation, see
http://www.itp.uni-hannover.de/~eckert/na/index.htm
ΠΠ½Π°Π»ΠΈΠ· ΡΡΡΡΠΊΡΡΡΡ Π±Π°ΠΊΡΠ΅ΡΠΈΠ΅ΠΌΠΈΠΉ ΠΈ ΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΊ Π°Π½ΡΠΈΠ±ΠΈΠΎΡΠΈΠΊΠ°ΠΌ ΠΌΠΈΠΊΡΠΎΠΎΡΠ³Π°Π½ΠΈΠ·ΠΌΠΎΠ², Π²ΡΠ΄Π΅Π»Π΅Π½Π½ΡΡ Π² ΠΎΡΠ΄Π΅Π»Π΅Π½ΠΈΡΡ ΡΠ΅Π°Π½ΠΈΠΌΠ°ΡΠΈΠΈ ΠΈ ΠΈΠ½ΡΠ΅Π½ΡΠΈΠ²Π½ΠΎΠΉ ΡΠ΅ΡΠ°ΠΏΠΈΠΈ Π² ΡΠΊΠΎΡΠΎΠΏΠΎΠΌΠΎΡΠ½ΠΎΠΌ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ΅ Π² ΠΏΠ΅ΡΠΈΠΎΠ΄ Ρ 2003 ΠΏΠΎ 2021 Π³.: ΡΠ΅ΡΡΠΎΡΠΏΠ΅ΠΊΡΠΈΠ²Π½ΠΎΠ΅ Π½Π°Π±Π»ΡΠ΄Π°ΡΠ΅Π»ΡΠ½ΠΎΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅
ΠΠΠ’Π£ΠΠΠ¬ΠΠΠ‘Π’Π¬: Π‘ΠΎΠ·Π΄Π°Π½ΠΈΠ΅ ΠΏΡΠΎΡΠΎΠΊΠΎΠ»ΠΎΠ² ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΠΉ ΡΠΌΠΏΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π°Π½ΡΠΈΠΌΠΈΠΊΡΠΎΠ±Π½ΠΎΠΉ ΡΠ΅ΡΠ°ΠΏΠΈΠΈ Π½Π΅Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎ Π±Π΅Π· Π°Π½Π°Π»ΠΈΠ·Π° Π°ΠΊΡΡΠ°Π»ΡΠ½ΡΡ
Π΄Π°Π½Π½ΡΡ
ΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΊΒ Π°Π½ΡΠΈΠ±ΠΈΠΎΡΠΈΠΊΠ°ΠΌ. Π¦ΠΠΠ¬ ΠΠ‘Π‘ΠΠΠΠΠΠΠΠΠ―: ΠΠ½Π°Π»ΠΈΠ· ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ ΡΡΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΉ Π·Π½Π°ΡΠΈΠΌΠΎΡΡΠΈ Π²Π΅Π΄ΡΡΠΈΡ
Π²ΠΎΠ·Π±ΡΠ΄ΠΈΡΠ΅Π»Π΅ΠΉ Π±Π°ΠΊΡΠ΅ΡΠΈΠ΅ΠΌΠΈΠΉ Π²Β ΠΎΡΠ΄Π΅Π»Π΅Π½ΠΈΠΈ ΡΠ΅Π°Π½ΠΈΠΌΠ°ΡΠΈΠΈ ΠΈΒ ΠΈΠ½ΡΠ΅Π½ΡΠΈΠ²Π½ΠΎΠΉ ΡΠ΅ΡΠ°ΠΏΠΈΠΈ (ΠΠ ΠΠ’) Π²Β ΠΏΠ΅ΡΠΈΠΎΠ΄ ΡΒ 2003 ΠΏΠΎ 2021Β Π³. ΠΈΒ ΠΈΡ
ΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΊΒ Π°Π½ΡΠΈΠ±ΠΈΠΎΡΠΈΠΊΠ°ΠΌ; ΠΈΠ·ΡΡΠ΅Π½ΠΈΠ΅ ΡΠΈΠΏΠΎΠ² ΠΊΠ°ΡΠ±Π°ΠΏΠ΅Π½Π΅ΠΌΠ°Π· ΡΒ Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ Π°ΠΊΡΡΠ°Π»ΡΠ½ΡΡ
Π²ΠΎΠ·Π±ΡΠ΄ΠΈΡΠ΅Π»Π΅ΠΉΒ β Klebsiella pneumoniae ΠΈΒ Acinetobacter baumannii. ΠΠΠ’ΠΠ ΠΠΠΠ« Π ΠΠΠ’ΠΠΠ«: ΠΒ Π°Π½Π°Π»ΠΈΠ· Π±ΡΠ»ΠΈ Π²ΠΊΠ»ΡΡΠ΅Π½Ρ Π²ΡΠ΅ ΠΊΠ»ΠΈΠ½ΠΈΡΠ΅ΡΠΊΠΈ Π·Π½Π°ΡΠΈΠΌΡΠ΅ ΠΌΠΈΠΊΡΠΎΠΎΡΠ³Π°Π½ΠΈΠ·ΠΌΡ, Π²ΡΠ΄Π΅Π»Π΅Π½Π½ΡΠ΅ ΠΈΠ· ΠΊΡΠΎΠ²ΠΈ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ², Π½Π°Ρ
ΠΎΠ΄ΠΈΠ²ΡΠΈΡ
ΡΡ ΠΠ ΠΠ’ ΠΎΠ±ΡΠ΅Π³ΠΎ ΠΏΡΠΎΡΠΈΠ»Ρ, ΡΠ°ΡΡΡΠΈΡΠ°Π½Π½ΠΎΠΌ Π½Π° 12Β ΠΊΠΎΠ΅ΠΊ, Π²Β ΡΠΊΠΎΡΠΎΠΏΠΎΠΌΠΎΡΠ½ΠΎΠΌ ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ΅ Π³.Β ΠΠΎΡΠΊΠ²Ρ Π²Β ΠΏΠ΅ΡΠΈΠΎΠ΄ ΡΒ 2003 ΠΏΠΎ 2021Β Π³. ΠΠ΄Π΅Π½ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΠΌΠΈΠΊΡΠΎΠΎΡΠ³Π°Π½ΠΈΠ·ΠΌΠΎΠ² ΠΈΒ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΡΡΠ²ΡΡΠ²ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΊΒ Π°Π½ΡΠΈΠ±ΠΈΠΎΡΠΈΠΊΠ°ΠΌ ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΠΈ Π²Β Π°Π²ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΌ Π°Π½Π°Π»ΠΈΠ·Π°ΡΠΎΡΠ΅ PHOENIX ΠΈΒ ΡΡΠ°Π½Π΄Π°ΡΡΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΡΠΌ Π΄ΠΈΡΠΊΠΎ-Π΄ΠΈΡΡΡΠ·ΠΈΠΎΠ½Π½ΡΠΌ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ. ΠΠ΅ΡΠ΅ΠΊΡΠΈΡ ΠΊΠ°ΡΠ±Π°ΠΏΠ΅Π½Π΅ΠΌΠ°Π· ΠΎΡΡΡΠ΅ΡΡΠ²Π»ΡΠ»ΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΏΠΎΠ»ΠΈΠΌΠ΅ΡΠ°Π·Π½ΠΎΠΉ ΡΠ΅ΠΏΠ½ΠΎΠΉ ΡΠ΅Π°ΠΊΡΠΈΠΈ. Π ΠΠΠ£ΠΠ¬Π’ΠΠ’Π«: ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΎ 17Β 034 ΠΎΠ±ΡΠ°Π·ΡΠ° ΠΊΡΠΎΠ²ΠΈ, ΠΈΠ· ΠΊΠΎΡΠΎΡΡΡ
Π±ΡΠ»ΠΎ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΎ 6372 ΠΌΠΈΠΊΡΠΎΠΎΡΠ³Π°Π½ΠΈΠ·ΠΌΠ°. ΠΒ ΡΠΊΠ°Π·Π°Π½Π½ΡΠΉ ΠΏΠ΅ΡΠΈΠΎΠ΄ Π΄ΠΎΠ»Ρ Π³ΡΠ°ΠΌΠΎΡΡΠΈΡΠ°ΡΠ΅Π»ΡΠ½ΡΡ
ΠΌΠΈΠΊΡΠΎΠΎΡΠ³Π°Π½ΠΈΠ·ΠΌΠΎΠ² ΡΠ²Π΅Π»ΠΈΡΠΈΠ»Π°ΡΡ ΡΒ 21,0 Π΄ΠΎ 52,8Β %, ΠΏΡΠ΅ΠΈΠΌΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎ Π·Π° ΡΡΠ΅Ρ K.Β pneumoniae (1,0β24,5Β %) ΠΈΒ A.Β baumannii (0β9,1Β %). Π£ΡΡΠΎΠΉΡΠΈΠ²ΠΎΡΡΡ ΡΡΠΈΡ
ΠΌΠΈΠΊΡΠΎΠΎΡΠ³Π°Π½ΠΈΠ·ΠΌΠΎΠ² ΠΊΒ ΠΊΠ°ΡΠ±Π°ΠΏΠ΅Π½Π΅ΠΌΠ°ΠΌ ΡΒ 2008 ΠΏΠΎ 2021Β Π³. Π·Π½Π°ΡΠΈΡΠ΅Π»ΡΠ½ΠΎ ΡΠ²Π΅Π»ΠΈΡΠΈΠ»Π°ΡΡ: K.Β pneumoniaeΒ β ΡΒ 2,3 Π΄ΠΎ 70,3Β %, A.Β baumanniiΒ β ΡΒ 7,5 Π΄ΠΎ 99,5Β %. Π¨ΡΠ°ΠΌΠΌΡ K.Β pneumoniae ΠΏΡΠΎΠ΄ΡΡΠΈΡΠΎΠ²Π°Π»ΠΈ ΡΠ»Π΅Π΄ΡΡΡΠΈΠ΅ ΡΠΈΠΏΡ ΠΊΠ°ΡΠ±Π°ΠΏΠ΅Π½Π΅ΠΌΠ°Π·: OXA-48 (73,8Β %), KPC (6,2Β %), NDM (1,5Β %), NDMΒ +Β OXA-48 (15,4Β %), KPCΒ +Β OXA-48 (3,1Β %). ΠΡΠ΅ ΡΡΠ°ΠΌΠΌΡ A.Β baumannii ΠΏΡΠΎΠ΄ΡΡΠΈΡΠΎΠ²Π°Π»ΠΈ ΠΊΠ°ΡΠ±Π°ΠΏΠ΅Π½Π΅ΠΌΠ°Π·Ρ OXA-40. ΠΡΠΎΠ΄ΡΡΠ΅Π½ΡΡ ΠΊΠ°ΡΠ±Π°ΠΏΠ΅Π½Π΅ΠΌΠ°Π·Ρ OXA-48 Π±ΡΠ»ΠΈ ΡΡΡΠΎΠΉΡΠΈΠ²Ρ ΠΊΒ ΠΊΠΎΠ»ΠΈΡΡΠΈΠ½Ρ ΠΈΒ ΡΠΈΠ³Π΅ΡΠΈΠΊΠ»ΠΈΠ½Ρ Π²Β 14,6 ΠΈΒ 44,8Β % ΡΠ»ΡΡΠ°Π΅Π² ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΠΎ, ΠΊΒ ΡΠ΅ΡΡΠ°Π·ΠΈΠ΄ΠΈΠΌΡ/Π°Π²ΠΈΠ±Π°ΠΊΡΠ°ΠΌΡΒ β Π²Β 4,2Β % ΡΠ»ΡΡΠ°Π΅Π². ΠΠ«ΠΠΠΠ«: Π£Π²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠ΅ ΡΡΠΎΠ²Π½Ρ Π°Π½ΡΠΈΠΌΠΈΠΊΡΠΎΠ±Π½ΠΎΠΉ ΡΠ΅Π·ΠΈΡΡΠ΅Π½ΡΠ½ΠΎΡΡΠΈ Π²Β ΠΏΠΎΡΠ»Π΅Π΄Π½ΠΈΠ΅ Π³ΠΎΠ΄Ρ ΡΡΠ΅Π΄ΠΈ Π΄ΠΎΠΌΠΈΠ½ΠΈΡΡΡΡΠΈΡ
Π²Β Π±Π°ΠΊΡΠ΅ΡΠΈΠ΅ΠΌΠΈΠΈ Π³ΡΠ°ΠΌΠΎΡΡΠΈΡΠ°ΡΠ΅Π»ΡΠ½ΡΡ
ΠΌΠΈΠΊΡΠΎΠΎΡΠ³Π°Π½ΠΈΠ·ΠΌΠΎΠ² ΡΠ²Π»ΡΠ΅ΡΡΡ ΠΎΡΠ΅Π½Ρ Π·Π½Π°ΡΠΈΠΌΠΎΠΉ ΠΏΡΠΎΠ±Π»Π΅ΠΌΠΎΠΉ Π²Β ΠΠ ΠΠ’. ΠΠΎΠ»ΡΡΠΈΠ½ΡΡΠ²ΠΎ ΡΡΠ°ΠΌΠΌΠΎΠ² K.Β pneumoniae Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΠ·ΡΡΡΡΡ ΠΌΠ½ΠΎΠΆΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠΉ ΡΠ΅Π·ΠΈΡΡΠ΅Π½ΡΠ½ΠΎΡΡΡΡ ΠΈΒ ΠΎΠΊΠΎΠ»ΠΎ 10Β %Β β ΡΠΊΡΡΡΠ΅ΠΌΠ°Π»ΡΠ½ΠΎΠΉ, ΠΈΠ»ΠΈ ΠΏΠ°Π½ΡΠ΅Π·ΠΈΡΡΠ΅Π½ΡΠ½ΠΎΡΡΡΡ. ΠΡΠ°ΠΊΡΠΈΡΠ΅ΡΠΊΠΈ Π²ΡΠ΅ ΡΡΠ°ΠΌΠΌΡ A.Β baumannii ΠΎΡΠ½ΠΎΡΡΡΡΡ ΠΊΒ ΠΊΠ°ΡΠ΅Π³ΠΎΡΠΈΠΈ ΡΠΊΡΡΡΠ΅ΠΌΠ°Π»ΡΠ½ΠΎ ΡΠ΅Π·ΠΈΡΡΠ΅Π½ΡΠ½ΡΡ
Studyng the effects of Cantharellus cibarius fungi on Opisthorchis felineus trematode and on parasite host - C57BL/6 inbred mice
Opisthorchiasis is a dangerous parasitic disease caused by trematodes in the family Opisthorchiidae. One of the causes of this infection is the species Opisthorchis felineus, which is common in the Russian Federation and Western Europe. The disease has a large number of complications and relatively few effective treatments, so nowadays it is relevant to look for new drugs for the treatment of opisthorchiasis, with the maximum antiparasitic and minimal side effect. In this work, a potentially anthelmintic effect of the methanol extract of the golden chanterelle mushroom (Cantharellus cibarius) was investigated. In in vitro experiments, the significantly reduced mobility and survival rates of juvenile O. felineus specimens with increasing concentrations (10-1000 pg/ml) of the C. cibarius extract were shown. In in vivo studies, administration of the C. cibarius extract on the first day after parasitic infection of inbred C57BL/6 mice resulted in a decrease of the number of helminths in the bile ducts of the liver, evaluated 6 weeks after infection. In another series of experiments, administration of the C. cibarius extract for 7 days to mice infected with O. felineus for five weeks had no anthelmintic effect. In both cases, the state of the infected hosts, evaluated by a number of physiological and biochemical parameters (relative weight of organs, blood indices), did not deteriorate, indicating that there was no adverse effect of the C. cibarius extract. The results obtained suggest that the C. cibarius extract might have anthelmintic properties if applied as parasite larvae excyst
- β¦