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

Quantum Switching of Entangled Photons based on Rydberg Blockade Effect

Dong-Sheng Ding, Yichen Yu, Ming‐Xin Dong, Ying-Hao Ye, Guang‐Can Guo, Bao‐Sen Shi

Published Mar 20, 2019• 0 citations
OpenAlex

Abstract

The long-range interaction between Rydberg-excited atoms endows a medium with large optical nonlinearity. Here, we demonstrate an optical switch to operate on a single photon from an entangled photon pair under a Rydberg electromagnetically induced transparency configuration. With the presence of the Rydberg blockade effect, we switch on a gate field to make the atomic medium nontransparent thereby absorbing the single photon emitted from another atomic ensemble via the spontaneous four-wave mixing process. In contrast to the case without a gate field, more than 50% of the photons sent to the switch are blocked, and finally achieve an effective single-photon switch. There are on average 1-2 gate photons per effective blockade sphere in one gate pulse. This switching effect on a single entangled photon depends on the principal quantum number and the photon number of the gate field. Our experimental progress is significant in the quantum information process especially in controlling the interaction between Rydberg atoms and entangled photon pairs.

Related papers

A Single-Photon Switch and Transistor based on Rydberg Blockade

Simon Baur

This thesis reports the experimental realisation of a single-photon switch and transistor.To this end, Rydberg blockade in electromagnetically induced transparency (EIT) is used to create an interaction between two light pulses at the single photon level.In the experiment, a gate pulse containing one incoming photon on average is stored as a Rydberg excitation in an ultracold atomic gas using EIT.Subsequently a target light pulse is sent through the atomic ensemble.Without the gate pulse, the medium would be transparent due to EIT and the transmission would be high.If a gate excitation has been stored, however, Rydberg blockade suppresses the transmission of the target light pulse.The stored gate photon can be retrieved after the transmission of the target light.A retrieved photon heralds successful storage.In the corresponding postselected subensemble the transmission of the target light is reduced by an extinction factor of 0.05.This reduction is robust if the number of incoming gate photons or target photons is varied.In a conceptually improved version of the experiment, a single-photon transistor is realised that shows a gain above unity.The gain quantifies the change in the transmitted target photon number per incoming gate photon.For one incoming gate photon on average, a gain of 20 is observed.The improved experiment uses a Förster resonance, the benefit of which becomes directly evident in an improved gain and extinction.If a Rydberg excitation is created during the gate pulse, then the transmission of the target light pulse drops substantially.By setting a discrimination threshold for the number of detected target photons, it is possible to detect in a single shot with a fidelity of 86% whether a Rydberg excitation was created during the gate pulse.Since the gate excitation is not retrieved by the target light, this detection method is nondestructive.i iii 6.2.Experimental Sequence . . . . . . .

•Jan 1, 2015•3 citations

Single-Photon Switch Based on Rydberg Blockade

Simon Baur, Daniel Tiarks, Gerhard Rempe +1 more

All-optical switching is a technique in which a gate light pulse changes the transmission of a target light pulse without the detour via electronic signal processing. We take this to the quantum regime, where the incoming gate light pulse contains only one photon on average. The gate pulse is stored as a Rydberg excitation in an ultracold atomic gas using electromagnetically induced transparency. Rydberg blockade suppresses the transmission of the subsequent target pulse. Finally, the stored gate photon can be retrieved. A retrieved photon heralds successful storage. The corresponding postselected subensemble shows an extinction of 0.05. The single-photon switch offers many interesting perspectives ranging from quantum communication to quantum information processing.

arXiv:1307.3509•Physical Review Letters•Feb 18, 2014•278 citations

Electromagnetically induced transparency and photon-photon interactions with Rydberg atoms

David Petrosyan, Michael Fleischhauer

We discuss electromagnetically induced transparency in a cold ensemble of atoms optically excited to the Rydberg states. Strong dipole-dipole or van der Waals interactions between the atomic Rydberg states translate into large nonlocal nonlinearities for a propagating probe field. In the case of weak quantum fields, this can be used to attain a conditional phase shift of π between pairs of single photons realizing a deterministic photonic phase gate. For stronger fields, long-range interactions between the atoms constrain the medium to behave as a collection of superatoms, each comprising a blockade volume that can accommodate at most one Rydberg excitation. The propagation of a probe field is affected by its two-photon correlations within the blockade distance, which are strongly damped due to low saturation threshold of the superatoms. Our calculations reproduce and interpret the results of recent experiments.

Journal of Physics Conference Series•Mar 14, 2012•3 citations

Single-Photon Absorber Based on Strongly Interacting Rydberg Atoms

Christoph Tresp, Christian Zimmer, Ivan Mirgorodskiy +3 more

We report on the realization of a free-space single-photon absorber, which deterministically absorbs exactly one photon from an input pulse. Our scheme is based on the saturation of an optically thick medium by a single photon due to Rydberg blockade. By converting one absorbed input photon into a stationary Rydberg excitation, decoupled from the light field through fast engineered dephasing, we blockade the full atomic cloud and change our optical medium from opaque to transparent. We show that this results in the subtraction of one photon from the input pulse over a wide range of input photon numbers. We investigate the change of the pulse shape and temporal photon statistics of the transmitted light pulses for different input photon numbers and compare the results to simulations. Based on the experimental results, we discuss the applicability of our single-photon absorber for number resolved photon detection schemes or quantum gate operations.

arXiv:1605.04456•Physical Review Letters•Nov 21, 2016•66 citations

Nonlinear modifications of photon correlations via controlled single and double Rydberg blockade

Yi-Mou Liu, Xue-Dong Tian, Dong Yan +3 more

We study the optical response of cold rubidium atoms driven into the four-level Y configuration exhibiting two high Rydberg levels in the regime of electromagnetically induced transparency (EIT). Atoms excited to either Rydberg level interact with each other just via self-blockade potentials (I) or also via cross blockade potentials (II). Numerical results show a few interesting quantum phenomena on the transmitted properties of a weak probe field owing to controlled single and double Rydberg blockade. In case (I), it is viable to switch between single-photon outputs with vanishing (invariable) two-photon (three-photon) correlation and photon-pair outputs with vanishing (invariable) three-photon (two-photon) correlation. Such output switch can be easily done by modulating frequencies and intensities of two strong coupling fields to create a degenerate EIT window or two separated EIT windows. In case (II), we find that two-photon and three-photon correlations decrease together at a degenerate EIT window center while increasing together between two separated EIT windows. Such consistent changes are observed because both correlations are modified by the identical polarizability degradation though depending on single and double Rydberg blockade, respectively.

Physical Review A•Apr 2, 2015•34 citations

Photonic controlled-phase gates through Rydberg blockade in optical cavities

Sumanta Das, Andrey Grankin, Ivan Iakoupov +7 more

We propose a scheme for high-fidelity photonic controlled-phase gates using a Rydberg blockade in an ensemble of atoms in an optical cavity. The gate operation is obtained by first storing a photonic pulse in the ensemble and then scattering a second pulse from the cavity, resulting in a phase change depending on whether the first pulse contained a single photon. We show that the combination of a Rydberg blockade and optical cavities effectively enhances the optical nonlinearity created by the strong Rydberg interaction and makes the gate operation more robust. The resulting gate can be implemented with cavities of moderate finesse, allowing for highly efficient processing of quantum information encoded in photons. As an illustration, we show how the gate can be employed to increase the communication rate of quantum repeaters based on atomic ensembles.

arXiv:1506.04300•Physical Review A•Apr 11, 2016•66 citations
The long-range interaction between Rydberg-excited atoms endows a medium with large optical nonlinearity. Here, we demonstrate an optical switch to operate on a single photon from an entangled photon pair under a Rydberg electromagnetically induced transparency configuration. With the presence of the Rydberg blockade effect, we switch on a gate field to make the atomic medium nontransparent thereby absorbing the single photon emitted from another atomic ensemble via the spontaneous four-wave mixing process. In contrast to the case without a gate field, more than 50% of the photons sent to the switch are blocked, and finally achieve an effective single-photon switch. There are on average 1-2 gate photons per effective blockade sphere in one gate pulse. This switching effect on a single entangled photon depends on the principal quantum number and the photon number of the gate field. Our experimental progress is significant in the quantum information process especially in controlling the interaction between Rydberg atoms and entangled photon pairs.
This thesis reports the experimental realisation of a single-photon switch and transistor.To this end, Rydberg blockade in electromagnetically induced transparency (EIT) is used to create an interaction between two light pulses at the single photon level.In the experiment, a gate pulse containing one incoming photon on average is stored as a Rydberg excitation in an ultracold atomic gas using EIT.Subsequently a target light pulse is sent through the atomic ensemble.Without the gate pulse, the medium would be transparent due to EIT and the transmission would be high.If a gate excitation has been stored, however, Rydberg blockade suppresses the transmission of the target light pulse.The stored gate photon can be retrieved after the transmission of the target light.A retrieved photon heralds successful storage.In the corresponding postselected subensemble the transmission of the target light is reduced by an extinction factor of 0.05.This reduction is robust if the number of incoming gate photons or target photons is varied.In a conceptually improved version of the experiment, a single-photon transistor is realised that shows a gain above unity.The gain quantifies the change in the transmitted target photon number per incoming gate photon.For one incoming gate photon on average, a gain of 20 is observed.The improved experiment uses a Förster resonance, the benefit of which becomes directly evident in an improved gain and extinction.If a Rydberg excitation is created during the gate pulse, then the transmission of the target light pulse drops substantially.By setting a discrimination threshold for the number of detected target photons, it is possible to detect in a single shot with a fidelity of 86% whether a Rydberg excitation was created during the gate pulse.Since the gate excitation is not retrieved by the target light, this detection method is nondestructive.i iii 6.2.Experimental Sequence . . . . . . .
All-optical switching is a technique in which a gate light pulse changes the transmission of a target light pulse without the detour via electronic signal processing. We take this to the quantum regime, where the incoming gate light pulse contains only one photon on average. The gate pulse is stored as a Rydberg excitation in an ultracold atomic gas using electromagnetically induced transparency. Rydberg blockade suppresses the transmission of the subsequent target pulse. Finally, the stored gate photon can be retrieved. A retrieved photon heralds successful storage. The corresponding postselected subensemble shows an extinction of 0.05. The single-photon switch offers many interesting perspectives ranging from quantum communication to quantum information processing.
We discuss electromagnetically induced transparency in a cold ensemble of atoms optically excited to the Rydberg states. Strong dipole-dipole or van der Waals interactions between the atomic Rydberg states translate into large nonlocal nonlinearities for a propagating probe field. In the case of weak quantum fields, this can be used to attain a conditional phase shift of π between pairs of single photons realizing a deterministic photonic phase gate. For stronger fields, long-range interactions between the atoms constrain the medium to behave as a collection of superatoms, each comprising a blockade volume that can accommodate at most one Rydberg excitation. The propagation of a probe field is affected by its two-photon correlations within the blockade distance, which are strongly damped due to low saturation threshold of the superatoms. Our calculations reproduce and interpret the results of recent experiments.
We report on the realization of a free-space single-photon absorber, which deterministically absorbs exactly one photon from an input pulse. Our scheme is based on the saturation of an optically thick medium by a single photon due to Rydberg blockade. By converting one absorbed input photon into a stationary Rydberg excitation, decoupled from the light field through fast engineered dephasing, we blockade the full atomic cloud and change our optical medium from opaque to transparent. We show that this results in the subtraction of one photon from the input pulse over a wide range of input photon numbers. We investigate the change of the pulse shape and temporal photon statistics of the transmitted light pulses for different input photon numbers and compare the results to simulations. Based on the experimental results, we discuss the applicability of our single-photon absorber for number resolved photon detection schemes or quantum gate operations.
We study the optical response of cold rubidium atoms driven into the four-level Y configuration exhibiting two high Rydberg levels in the regime of electromagnetically induced transparency (EIT). Atoms excited to either Rydberg level interact with each other just via self-blockade potentials (I) or also via cross blockade potentials (II). Numerical results show a few interesting quantum phenomena on the transmitted properties of a weak probe field owing to controlled single and double Rydberg blockade. In case (I), it is viable to switch between single-photon outputs with vanishing (invariable) two-photon (three-photon) correlation and photon-pair outputs with vanishing (invariable) three-photon (two-photon) correlation. Such output switch can be easily done by modulating frequencies and intensities of two strong coupling fields to create a degenerate EIT window or two separated EIT windows. In case (II), we find that two-photon and three-photon correlations decrease together at a degenerate EIT window center while increasing together between two separated EIT windows. Such consistent changes are observed because both correlations are modified by the identical polarizability degradation though depending on single and double Rydberg blockade, respectively.
We propose a scheme for high-fidelity photonic controlled-phase gates using a Rydberg blockade in an ensemble of atoms in an optical cavity. The gate operation is obtained by first storing a photonic pulse in the ensemble and then scattering a second pulse from the cavity, resulting in a phase change depending on whether the first pulse contained a single photon. We show that the combination of a Rydberg blockade and optical cavities effectively enhances the optical nonlinearity created by the strong Rydberg interaction and makes the gate operation more robust. The resulting gate can be implemented with cavities of moderate finesse, allowing for highly efficient processing of quantum information encoded in photons. As an illustration, we show how the gate can be employed to increase the communication rate of quantum repeaters based on atomic ensembles.