127 research outputs found
On measuring changes in welfare when changes in consumption bundles are small
The paper examines three extensively used propositions regarding changes in utility and social welfare attributable to small changes in consumption bundles. It is shown that, though these propositions are valid when the changes in consumption bundles are ``infinitesimally small,''' none of the propositions can be sustained when we have finite changes in consumption bundles, even when such finite changes are arbitrarily small. This drastically reduces the usefulness of the propositions for any practical purpose. The paper discusses the underlying formal structure of the problem and identifies the reason why the propositions run into difficulties in the case of finite changes.
Koherentno upravljanje spektrom spontane emisije u dvojno tjeranom atomu tipa Y
We have studied the dynamic control of the spontaneous emission spectrum in a Y-type atomic system driven by two coherent fields. In different dynamic conditions, the evolution of coherent spectral features in the bare-state model, has been analyzed by using the dressed-state model. For the system under purely dissipative environment, it has been shown that the behaviour of spectral components can be coherently controlled by changing the values of the Rabi frequencies and detunings of external fields. At the condition of resonant evolution of spectra, present work highlights that the emission line shape can be strongly modified for unequal decay rates of the uppermost doublet states. In this situation, the phenomenon of constructive quantum interference gives rise to the emergence of a single peak at a certain spectral position when two distinct peaks disappear at the other spectral positions. Owing to the mutual orientation of polarizations of the fields interacting with the atom in a specific configuration, we have incorporated the static phase-variation effect to exhibit phase-dependent spectra. We consider the present model with a typical field configuration such that the frequency mismatch between two coherent fields introduces the dynamic phase-variation effect. This phenomenon leads to obtain anomalous peak-shifting effect accompanied by the selective quenching of emission within the spectral profile.ProuÄavamo dinamiÄko upravljanje spektrom spontane emisije atomskog sustava tipa Y koji tjeraju dva koherentna polja. ProuÄavamo ovisnost svojstava koherentnog spektra o razliÄitim uvjetima, u oguljenom sustavu i primjenom potpunog sustava. Ako sustav troÅ”i energiju, onda svojstvima spektralnih sastavnica možemo koherentno upravljati mijenjanjem Rabijevih frekvencija i naruÅ”avanjem ugodbe vanjskih polja. Uz uvjet rezonantnog razvoja spektra, pokazujemo kako se oblik emisijske linije može jako promijeniti uz nejednoliko raspadanje gornjeg dubleta. U tim uvjetima konstruktivna kvantna interferencija uzrokuje nastanak jednog vrha na odreÄenom mjestu u spektru kada dva jasna vrha nestanu u drugim dijelovima spektra. Radi meÄusobne orijentacije polarizacija polja koja djeluju na atom u nekom stanju, ukljuÄili smo i uÄinak promjene statiÄke faze da bismo prikazali faznoovisne spektre. Ovaj model predstavljamo s tipiÄnim oblikom polja tako da nesklad frekvencija dovodi do dinamiÄkih promjena faze. Ta pojava vodi na anomalne pomake vrhova i moguÄnost odabira guÅ”enja emisije unutar spektralnog podruÄja
Koherentno upravljanje spektrom spontane emisije u dvojno tjeranom atomu tipa Y
We have studied the dynamic control of the spontaneous emission spectrum in a Y-type atomic system driven by two coherent fields. In different dynamic conditions, the evolution of coherent spectral features in the bare-state model, has been analyzed by using the dressed-state model. For the system under purely dissipative environment, it has been shown that the behaviour of spectral components can be coherently controlled by changing the values of the Rabi frequencies and detunings of external fields. At the condition of resonant evolution of spectra, present work highlights that the emission line shape can be strongly modified for unequal decay rates of the uppermost doublet states. In this situation, the phenomenon of constructive quantum interference gives rise to the emergence of a single peak at a certain spectral position when two distinct peaks disappear at the other spectral positions. Owing to the mutual orientation of polarizations of the fields interacting with the atom in a specific configuration, we have incorporated the static phase-variation effect to exhibit phase-dependent spectra. We consider the present model with a typical field configuration such that the frequency mismatch between two coherent fields introduces the dynamic phase-variation effect. This phenomenon leads to obtain anomalous peak-shifting effect accompanied by the selective quenching of emission within the spectral profile.ProuÄavamo dinamiÄko upravljanje spektrom spontane emisije atomskog sustava tipa Y koji tjeraju dva koherentna polja. ProuÄavamo ovisnost svojstava koherentnog spektra o razliÄitim uvjetima, u oguljenom sustavu i primjenom potpunog sustava. Ako sustav troÅ”i energiju, onda svojstvima spektralnih sastavnica možemo koherentno upravljati mijenjanjem Rabijevih frekvencija i naruÅ”avanjem ugodbe vanjskih polja. Uz uvjet rezonantnog razvoja spektra, pokazujemo kako se oblik emisijske linije može jako promijeniti uz nejednoliko raspadanje gornjeg dubleta. U tim uvjetima konstruktivna kvantna interferencija uzrokuje nastanak jednog vrha na odreÄenom mjestu u spektru kada dva jasna vrha nestanu u drugim dijelovima spektra. Radi meÄusobne orijentacije polarizacija polja koja djeluju na atom u nekom stanju, ukljuÄili smo i uÄinak promjene statiÄke faze da bismo prikazali faznoovisne spektre. Ovaj model predstavljamo s tipiÄnim oblikom polja tako da nesklad frekvencija dovodi do dinamiÄkih promjena faze. Ta pojava vodi na anomalne pomake vrhova i moguÄnost odabira guÅ”enja emisije unutar spektralnog podruÄja
On arithmetic functions of balancing and Lucas-balancing numbers
For any integers and let and denote the Euler phi function and the sum of the -th powers of the divisors of , respectively. In this article, the solutions to some Diophantine equations about these functions of balancing and Lucas-balancing numbers are discussed
ProuÄavanje uÄinaka brzinski-ovisnih sudara na lambovu udubinu i prijelazne rezonancije u sustavu s tri stanja
We discuss the effects of phase-dephasing and velocity-changing collisions on saturated absorption line shapes studied in an open V-type system under the semi-classical density-matrix formalism. It has been noted that the traces of Lamb dips and crossover resonance dip lying within the Doppler-broadened contour can vanish in the presence of a strong saturating field if a sufficient contribution of collisional dephasing effect is present. Asymmetry may be introduced in the wings of saturated line profiles for a small contribution of collision kernel.Raspravljamo uÄinke otklanjanja faze i sudara s promjenom brzine na oblike linija zasiÄenih apsorpcijom za otvoren V-sustav, primjenom poluklasiÄnog formalizma matrice gustoÄe. Primijetili smo da tragovi Lambovih udubina i prijelaznih rezonancija unutar linija proÅ”irenih Dopplerovih uÄinkom mogu nestati pod djelovanjem snažnog zasiÄujeÄeg polja uz dovoljan doprinos uÄinka sudarnog otklanjanja faza. U ramenima zasiÄenih linija može se postiÄi nesimetrija za male doprinose sudarne jezgre
ProuÄavanje uÄinaka brzinski-ovisnih sudara na lambovu udubinu i prijelazne rezonancije u sustavu s tri stanja
We discuss the effects of phase-dephasing and velocity-changing collisions on saturated absorption line shapes studied in an open V-type system under the semi-classical density-matrix formalism. It has been noted that the traces of Lamb dips and crossover resonance dip lying within the Doppler-broadened contour can vanish in the presence of a strong saturating field if a sufficient contribution of collisional dephasing effect is present. Asymmetry may be introduced in the wings of saturated line profiles for a small contribution of collision kernel.Raspravljamo uÄinke otklanjanja faze i sudara s promjenom brzine na oblike linija zasiÄenih apsorpcijom za otvoren V-sustav, primjenom poluklasiÄnog formalizma matrice gustoÄe. Primijetili smo da tragovi Lambovih udubina i prijelaznih rezonancija unutar linija proÅ”irenih Dopplerovih uÄinkom mogu nestati pod djelovanjem snažnog zasiÄujeÄeg polja uz dovoljan doprinos uÄinka sudarnog otklanjanja faza. U ramenima zasiÄenih linija može se postiÄi nesimetrija za male doprinose sudarne jezgre
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