Constraints on dephasing widths and shifts in three-level quantum systems

Berman, P. R.; O'Connell, Ross C.

doi:10.1103/physreva.71.022501

Cited by 11 publications

(8 citation statements)

References 4 publications

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“…With the values of collisional dephasing rates limited by this relation, we observed that our total population always remained constant. Our results complement the work in [13,14].…”

supporting

confidence: 94%

Impact of decoherence on internal state cooling using optical frequency combs

Malinovskaya¹,

Horton²

2013

J. Opt. Soc. Am. B

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We discuss femtosecond Raman-type techniques to control molecular vibrations, which can be implemented for internal-state cooling from Feshbach states with the use of optical frequency combs (OFCs) with and without modulation. The technique makes use of multiple two-photon resonances induced by optical frequencies present in the comb. It provides us with a useful tool to study the details of molecular dynamics at ultracold temperatures. In our theoretical model we take into account decoherence in the form of spontaneous emission and collisional dephasing in order to ascertain an accurate model of the population transfer in the three-level system. We analyze the effects of odd and even chirps of the OFC in the form of sine and cosine functions on the population transfer. We compare the effects of these chirps to the results attained with the standard OFC to see if they increase the population transfer to the final deeply bound state in the presence of decoherence. We also analyze the inherent phase relation that takes place owing to collisional dephasing between molecules in each of the states. This ability to control the rovibrational states of a molecule with an OFC enables us to create deeply bound ultra-cold polar molecules from the Feshbach state.Decoherence at ultracold temperatures is a subject of particular interest and importance in light of the development of methods to manipulate ultracold gases, create and control ultracold molecules [1-3], and study ultracold collisions and chemical reactions [4]. Decoherence is inherently present in ultracold dynamics, and we study it semiclassically within the process of creation of diatomic KRb molecules from Feshbach weakly bound states. Experimentally, ultracold polar KRb molecules were obtained using stimulated Raman adiabatic passage (STIRAP) [5]. As a viable substitute to the STIRAP process, we created a method that makes use of optical frequency combs (OFCs) to perform two-photon resonances and transfer population in a stepwise manner from the Feshbach state to the ground, ultracold state. The implementation of an OFC may be beneficial owing to its intrinsic ability to address the manifold of excited states simultaneously. We make use of a standard OFC and one with sinusoidal phase modulation to induce two-photon Raman transitions. Our theory demonstrates that the impact of decoherence may be minimized by implementing the sinusoidally modulated OFC.The standard OFC is generated by the phase-locked pulse train of the formEquation (1) gives a periodic envelope of the field which oscillates with an optical carrier frequency ω L , and k is an integer number. The pulse-train period T is much greater than τ, where τ is an individual pulse duration. A strictly periodic envelope function can be expressed as a power spectrum by the Fourier series, which is a comb of laser frequencies precisely spaced by the pulse-repetition rate ω r equal to 1∕T. Thus, the period of the pulse train determines the spacing between modes in the frequency comb and may be within a 10 ns ti...

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“…With the values of collisional dephasing rates limited by this relation, we observed that our total population always remained constant. Our results complement the work in [13,14].…”

supporting

confidence: 94%

Impact of decoherence on internal state cooling using optical frequency combs

Malinovskaya¹,

Horton²

2013

J. Opt. Soc. Am. B

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“…one observes a useful identity (23). Indeed, applying X † X, X † to X in (46), the left hand side of ( 23) is computed as…”

Section: The Bound Is Tightmentioning

confidence: 99%

“…in [20,21]. Some constraints for relaxation rates for 3-and 4-level systems were presented in [22][23][24]. Interestingly, authors of a sem-inal paper [2] already observed that for a qubit evolution governed by the following well known generator…”

mentioning

confidence: 99%

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On the universal constraints for relaxation rates for quantum dynamical semigroup

Chruscinski,

Kimura,

Kossakowski

et al. 2020

Preprint

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A conjecture for the universal constraints for relaxation rates of a quantum dynamical semigroup is proposed. It is shown that it holds for several interesting classes of semigroups, e.g. unital semigroups and semigroups derived in the weak coupling limit from the proper microscopic model. Moreover, proposed conjecture is supported by numerical analysis. This conjecture has several important implications: it allows to provide universal constraints for spectra of quantum channels and provides necessary condition to decide whether a given channel is consistent with Markovian evolution.

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“…These off-diagonal decay rates assume that all decoherence is due to population decay, which is suitable for atomic vapors. The values were chosen to be physically consistent with a positive density matrix, which does not always hold for arbitrary decoherence terms [36,37]. The branching ratio between the Γ 23 and Γ 13 decay channels was set to 0.65 : 0.35 as given in Ref.…”

Section: A Atomic Modelmentioning

confidence: 99%

All-optical microdisk switch using EIT

Clader¹,

Hendrickson²,

Camacho³

et al. 2013

Opt. Express

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We present theoretical results of a low-loss all-optical switch based on electromagnetically induced transparency and the classical Zeno effect in a microdisk resonator. We show that a control beam can modify the atomic absorption of the evanescent field which suppresses the cavity field buildup and alters the path of a weak signal beam. We predict more than 35 dB of switching contrast with less than 0.1 dB loss using just 2 µW of control-beam power for signal beams with less than single photon intensities inside the cavity.

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Constraints on dephasing widths and shifts in three-level quantum systems

Cited by 11 publications

References 4 publications

Impact of decoherence on internal state cooling using optical frequency combs

Impact of decoherence on internal state cooling using optical frequency combs

On the universal constraints for relaxation rates for quantum dynamical semigroup

All-optical microdisk switch using EIT

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