Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review Letters

Classical Behavior with Small Quantum Numbers: The Physics of Ramsey Interferometry of Rydberg Atoms

J. I. Kim, K. M. Fonseca-Romero, A. M. Horiguti, L. Davidovich, Maria Carolina Nemes, A. F. R. de Toledo Piza

Published Jun 14, 1999• 34 citations
Publisher

Abstract

In Ramsey atomic interferometry, a superposition of atomic states is produced by a mechanism completely equivalent (for experimental purposes) to interaction with a classical field. Since this property holds, in the case of Rydberg atoms, for temperatures close to absolute zero and field intensities of the order of a single photon, the question arises as to why the quantum nature of the field can be neglected. We model the passage of an atom through a Ramsey zone and show that, in order to explain the phenomenon, correlation properties between three subsystems and strong cavity dissipation turn out to be the essential physical ingredients leading to classical behavior.

DOI
10.1103/physrevlett.82.4737

Related papers

Emergence of classicality in small-number entangled systems

Eduardo Mascarenhas, Marcelo França Santos

We show the transition from a fully quantized interaction to a semiclassical one in entangled small-number quantum systems using the quantum trajectories approach. In particular, we simulate the microwave Ramsey zones used in Rydberg-atom interferometry, filling in the gap between the strongly entangling Jaynes-Cummings evolution and the semiclassical rotation of the atomic internal states. We also correlate the information flowing with leaking photons to the entanglement generation between cavity field and flying atom and detail the roles played by the strong dissipation and the external driving force in preserving atomic coherence through the interaction.

arXiv:0809.5184•Physical Review A•Feb 26, 2009•3 citations

Single-atom and two-atom Ramsey interferometry with quantized fields

G. S. Agarwal, Pradyumna K. Pathak, Marlan O. Scully

Implications of field quantization on Ramsey interferometry are discussed and general conditions for the occurrence of interference are obtained. Interferences do not occur if the fields in two Ramsey zones have a precise number of photons. However, in this case we show how an analog of Hanbury-Brown Twiss photon-photon correlation interferometry can be used to discern a variety of interference effects as the two independent Ramsey zones get entangled by the passage of the first atom. Interferences are restored by working with fields at a single-photon level. Generation of entangled states including states such as $|2,0〉{+e}^{i\ensuremath{\theta}}|0,2〉$ is discussed.

arXiv:quant-ph/0207111•Physical Review A•Apr 11, 2003•8 citations

Ramsey Interferometry with Quantized Fields

G. S. Agarwal, Pradyumna K. Pathak, Marlan O. Scully

Implications of field quantization on Ramsey interferometry are discussed and general conditions for the occurrence of interference are obtained. Interferences do not occur if the fields in two Ramsey zones have precise number of photons. However in this case we show how two atom (like two photon) interferometry can be used to discern a variety of interference effects as the two independent Ramsey zones get entangled by the passage of first atom. PACS number(s): 03.75.Dg, 03.65.Ud, 42.50.-p Typeset using REVTEX 1 The method of using spatially separated fields as proposed by Ramsey has been proved to be very useful for high resolution work. It was originally proposed as a technique in the microwave domain [1] which was then extended to studies in optical domain [2]. More recently this technique has been used very successfully in the studies of quantum entanglement resulting from the interaction of atoms with radiation in a high quality cavity. In this context Ramsey technique enables one to study the entanglement in different basis of states

•Jul 19, 2002•0 citations

Realization of a Rydberg-Dressed Ramsey Interferometer and Electrometer

A. Arias, G. Lochead, T. M. Wintermantel +2 more

We present the experimental realization and characterization of a Ramsey interferometer based on optically trapped ultracold potassium atoms, where one state is continuously coupled by an off-resonant laser field to a highly excited Rydberg state. We show that the observed interference signals can be used to precisely measure the Rydberg atom-light coupling strength as well as the population and coherence decay rates of the Rydberg-dressed states with subkilohertz accuracy and for Rydberg state fractions as small as one part in 10^{6}. We also demonstrate an application for measuring small, static electric fields with high sensitivity. This provides the means to combine the outstanding coherence properties of Ramsey interferometers based on atomic ground states with a controllable coupling to strongly interacting states, thus expanding the number of systems suitable for metrological applications and many-body physics studies.

arXiv:1810.04151•Physical Review Letters•Feb 6, 2019•50 citations

Decoherence, Wigner functions, and the classical limit of quantum mechanics in cavity QED

L. Davidovich

Recent experiments in cavity QED have allowed the monitoring of the decoherence process, which is at the heart of the quantum theory of measurement and plays an essential role in the classical limit of quantum mechanics. It is shown here that the technique of Ramsey interferometry, central to those experiments, may be used to determine completely the quantum state of an electromagnetic field in a cavity. This new method, which allows the direct measurement of the Wigner function of the field, is a useful tool for probing the quantum-classical transition and, in particular, the decoherence of superpositions of distinguishable coherent states of the electromagnetic field in the cavity. It is also shown that the realization of a controlled-not gate within the framework of cavity QED is a special case of this proposal, and is related to the measurement of the Wigner function of a one-photon state.

Mysteries, Puzzles, and Paradoxes in Quantum Mechanics•Jan 1, 1999•1 citation

Ramsey interferometry of Rydberg ensembles inside microwave cavities

Christian Sommer, Claudiu Genes

We study ensembles of Rydberg atoms in a confined electromagnetic environment such as is provided by a microwave cavity. The competition between standard free space Ising type and cavity-mediated interactions leads to the emergence of different regimes where the particle−particle couplings range from the typical van der Waals r −6 behavior to r −3 and to r -independence. We apply a Ramsey spectroscopic technique to map the two-body interactions into a characteristic signal such as intensity and contrast decay curves. As opposed to previous treatments requiring high-densities for considerable contrast and phase decay (Takei et al 2016 Nat. Comms. 7 13449; Sommer et al 2016 Phys. Rev. A 94 053607), the cavity scenario can exhibit similar behavior at much lower densities.

arXiv:1710.07582•Journal of Physics B Atomic Molecular and Optical Physics•Apr 12, 2018•0 citations
In Ramsey atomic interferometry, a superposition of atomic states is produced by a mechanism completely equivalent (for experimental purposes) to interaction with a classical field. Since this property holds, in the case of Rydberg atoms, for temperatures close to absolute zero and field intensities of the order of a single photon, the question arises as to why the quantum nature of the field can be neglected. We model the passage of an atom through a Ramsey zone and show that, in order to explain the phenomenon, correlation properties between three subsystems and strong cavity dissipation turn out to be the essential physical ingredients leading to classical behavior.
We show the transition from a fully quantized interaction to a semiclassical one in entangled small-number quantum systems using the quantum trajectories approach. In particular, we simulate the microwave Ramsey zones used in Rydberg-atom interferometry, filling in the gap between the strongly entangling Jaynes-Cummings evolution and the semiclassical rotation of the atomic internal states. We also correlate the information flowing with leaking photons to the entanglement generation between cavity field and flying atom and detail the roles played by the strong dissipation and the external driving force in preserving atomic coherence through the interaction.
Implications of field quantization on Ramsey interferometry are discussed and general conditions for the occurrence of interference are obtained. Interferences do not occur if the fields in two Ramsey zones have a precise number of photons. However, in this case we show how an analog of Hanbury-Brown Twiss photon-photon correlation interferometry can be used to discern a variety of interference effects as the two independent Ramsey zones get entangled by the passage of the first atom. Interferences are restored by working with fields at a single-photon level. Generation of entangled states including states such as $|2,0〉{+e}^{i\ensuremath{\theta}}|0,2〉$ is discussed.
Implications of field quantization on Ramsey interferometry are discussed and general conditions for the occurrence of interference are obtained. Interferences do not occur if the fields in two Ramsey zones have precise number of photons. However in this case we show how two atom (like two photon) interferometry can be used to discern a variety of interference effects as the two independent Ramsey zones get entangled by the passage of first atom. PACS number(s): 03.75.Dg, 03.65.Ud, 42.50.-p Typeset using REVTEX 1 The method of using spatially separated fields as proposed by Ramsey has been proved to be very useful for high resolution work. It was originally proposed as a technique in the microwave domain [1] which was then extended to studies in optical domain [2]. More recently this technique has been used very successfully in the studies of quantum entanglement resulting from the interaction of atoms with radiation in a high quality cavity. In this context Ramsey technique enables one to study the entanglement in different basis of states
We present the experimental realization and characterization of a Ramsey interferometer based on optically trapped ultracold potassium atoms, where one state is continuously coupled by an off-resonant laser field to a highly excited Rydberg state. We show that the observed interference signals can be used to precisely measure the Rydberg atom-light coupling strength as well as the population and coherence decay rates of the Rydberg-dressed states with subkilohertz accuracy and for Rydberg state fractions as small as one part in 10^{6}. We also demonstrate an application for measuring small, static electric fields with high sensitivity. This provides the means to combine the outstanding coherence properties of Ramsey interferometers based on atomic ground states with a controllable coupling to strongly interacting states, thus expanding the number of systems suitable for metrological applications and many-body physics studies.
Recent experiments in cavity QED have allowed the monitoring of the decoherence process, which is at the heart of the quantum theory of measurement and plays an essential role in the classical limit of quantum mechanics. It is shown here that the technique of Ramsey interferometry, central to those experiments, may be used to determine completely the quantum state of an electromagnetic field in a cavity. This new method, which allows the direct measurement of the Wigner function of the field, is a useful tool for probing the quantum-classical transition and, in particular, the decoherence of superpositions of distinguishable coherent states of the electromagnetic field in the cavity. It is also shown that the realization of a controlled-not gate within the framework of cavity QED is a special case of this proposal, and is related to the measurement of the Wigner function of a one-photon state.
We study ensembles of Rydberg atoms in a confined electromagnetic environment such as is provided by a microwave cavity. The competition between standard free space Ising type and cavity-mediated interactions leads to the emergence of different regimes where the particle−particle couplings range from the typical van der Waals r −6 behavior to r −3 and to r -independence. We apply a Ramsey spectroscopic technique to map the two-body interactions into a characteristic signal such as intensity and contrast decay curves. As opposed to previous treatments requiring high-densities for considerable contrast and phase decay (Takei et al 2016 Nat. Comms. 7 13449; Sommer et al 2016 Phys. Rev. A 94 053607), the cavity scenario can exhibit similar behavior at much lower densities.