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

arXiv:1309.2514 · Physical Review A

Quantum interference of a single spin excitation with a macroscopic atomic ensemble

S. L. Christensen, J.-B. Béguin, Eva Bookjans, H. L. Sørensen, Jörg Helge Müller, J. Appel, Eugene Simon Polzik

Published Mar 3, 2014• 30 citations
arXivHTMLPDF

Abstract

We report on the observation of quantum interference of a collective single spin excitation with a spin ensemble of ${N}_{\mathrm{a}}\ensuremath{\approx}{10}^{5}$ atoms. Detection of a single photon scattered from the atoms creates the single spin excitation, a Fock state embedded in the collective spin of the ensemble. The state of the atomic ensemble is then detected by a quantum nondemolition measurement of the collective spin. A macroscopic difference of the order of ${\sqrt{N}}_{\mathrm{a}}$ in the marginal distribution of the collective spin state arises from the interference between the single excited spin and ${N}_{\mathrm{a}}$ atoms. These hybrid discrete-continuous manipulation and measurement procedures of collective spin states in an atomic ensemble pave the road towards generation of even more exotic ensemble states for quantum information processing, precision measurements, and communication.

DOI
10.1103/physreva.89.033801

Related papers

‘Which-way’ collective atomic spin excitation among atomic ensembles by photon indistinguishability

Guowan Zhang, Chenglin Bian, Liang Chen +2 more

In spontaneous Raman scattering in an atomic ensemble, a collective atomic spin wave is created in correlation with the Stokes field. When the Stokes photons from two or more such atomic ensembles are made indistinguishable, a 'which-way' collective atomic spin excitation is generated among the independent atomic ensembles. We demonstrate this phenomenon experimentally by reading out the atomic spin excitations and observing interference between the read-out beams. When a single-photon projective measurement is made on the indistinguishable Stokes photons, this simple scheme can be used to entangle independent atomic ensembles. Compared to other currently used methods, this scheme can be easily scaled up and has greater efficiency.

New Journal of Physics•Jun 25, 2012•6 citations

Hong-Ou-Mandel Interference between Two Deterministic Collective Excitations in an Atomic Ensemble

Jun Li, Ming-Ti Zhou, Bo Jing +6 more

We demonstrate deterministic generation of two distinct collective excitations in one atomic ensemble, and we realize the Hong-Ou-Mandel interference between them. Using Rydberg blockade we create single collective excitations in two different Zeeman levels, and we use stimulated Raman transitions to perform a beam-splitter operation between the excited atomic modes. By converting the atomic excitations into photons, the two-excitation interference is measured by photon coincidence detection with a visibility of 0.89(6). The Hong-Ou-Mandel interference witnesses an entangled NOON state of the collective atomic excitations, and we demonstrate its two times enhanced sensitivity to a magnetic field compared with a single excitation. Our work implements a minimal instance of boson sampling and paves the way for further multimode and multiexcitation studies with collective excitations of atomic ensembles.

arXiv:1608.03076•Physical Review Letters•Oct 24, 2016•41 citations

Quantum nondemolition measurements of collective atomic spin

A. Kuzmich, L. Mandeļ, J. Janis +3 more

We have performed quantum nondemolition measurements on the collective spin of $\ensuremath{\sim}{10}^{6}$ cesium atoms. In this way ensembles of atoms with sub-shot-noise fluctuations of a collective spin have been prepared. These observations open the way toward the generation of squeezed spin states of atoms.

Physical Review A•Sep 1, 1999•121 citations

Quantum information with atomic ensembles

P. Zoller

We summarize our recent work on quantum information with atomic ensembles. In particular, we describe techniques for storing and manipulating quantum information in collective states of mesoscopic ensembles. Quantum information processing is is accomplished by optical excitation into states with strong dipole-dipole interactions. The resulting “dipole blockade” can be used to inhibit transitions into all but singly excited collective states. This can be employed for a controlled generation of collective atomic spin states as well as non-classical photonic states and for scalable quantum logic gates. Furthermore, we present schemes for entangling a very large number of atoms of a spinor 1 Bose Einstein condensate based on collisional interaction between atoms. As a final example, we discuss the possiblilty of creating entangled atomic states of a few bosonic atoms in a setup which mimics a “fractional quantum Hall effect” and allows the manipulation of anyonic excitations.

Optical Fiber Communication Conference•Jan 1, 2001•0 citations

How to measure the quantum state of collective atomic spin excitation

Koji Usami, Jun-ichi Takahashi, Mikio Kozuma

The spin state of an atomic ensemble can be viewed as two bosonic modes, i.e., a quantum signal mode and a $c$-numbered ``local oscillator'' mode when large numbers of spin-1/2 atoms are spin polarized along a certain axis and collectively manipulated within the vicinity of the axis. We present a concrete procedure, which determines the spin-excitation-number distribution, i.e., the diagonal elements of the density matrix in the Dicke basis for the collective spin state. By seeing the collective spin state as a statistical mixture of the inherently entangled Dicke states, the physical picture of its multiparticle entanglement is made clear.

arXiv:quant-ph/0609054•Physical Review A•Oct 19, 2006•4 citations

Entanglement and quantum memory with atomic ensembles

Eugene Simon Polzik, Brian Julsgaard, Jens Lykke Sørensen +1 more

Summary form only given. A new approach to the problem of the quantum interface between light and atoms has been recently developed. The method utilizes free space dispersive interaction between pulses of light and spin polarized atomic ensembles. Entanglement between the polarization state of light and the collective spin state of atoms is established by measurement, more precisely by detection of light in a certain polarization basis. In the first demonstration of this approach we have generated a long-lived entangled state of two separate macroscopic atomic samples by a polarization measurement on light transmitted through the samples. We then have shown that this approach also works for mapping of a quantum state of light onto long-lived atomic spin state paving the road towards realization of the quantum memory for light. Recently we have also extended the free space light-atoms interface beyond the continuous variables in the proposal, where a coherent superposition "cat" state of an atomic ensemble is generated by a measurement sequence. Progress with other communication protocols such as atomic state teleportation and multiparty networks will be presented.

European Quantum Electronics Conference (EQEC)•Jan 1, 2003•0 citations
We report on the observation of quantum interference of a collective single spin excitation with a spin ensemble of Na\ensuremath≈105{N}_{\mathrm{a}}\ensuremath{\approx}{10}^{5}Na​\ensuremath≈105 atoms. Detection of a single photon scattered from the atoms creates the single spin excitation, a Fock state embedded in the collective spin of the ensemble. The state of the atomic ensemble is then detected by a quantum nondemolition measurement of the collective spin. A macroscopic difference of the order of Na{\sqrt{N}}_{\mathrm{a}}N​a​ in the marginal distribution of the collective spin state arises from the interference between the single excited spin and Na{N}_{\mathrm{a}}Na​ atoms. These hybrid discrete-continuous manipulation and measurement procedures of collective spin states in an atomic ensemble pave the road towards generation of even more exotic ensemble states for quantum information processing, precision measurements, and communication.
In spontaneous Raman scattering in an atomic ensemble, a collective atomic spin wave is created in correlation with the Stokes field. When the Stokes photons from two or more such atomic ensembles are made indistinguishable, a 'which-way' collective atomic spin excitation is generated among the independent atomic ensembles. We demonstrate this phenomenon experimentally by reading out the atomic spin excitations and observing interference between the read-out beams. When a single-photon projective measurement is made on the indistinguishable Stokes photons, this simple scheme can be used to entangle independent atomic ensembles. Compared to other currently used methods, this scheme can be easily scaled up and has greater efficiency.
We demonstrate deterministic generation of two distinct collective excitations in one atomic ensemble, and we realize the Hong-Ou-Mandel interference between them. Using Rydberg blockade we create single collective excitations in two different Zeeman levels, and we use stimulated Raman transitions to perform a beam-splitter operation between the excited atomic modes. By converting the atomic excitations into photons, the two-excitation interference is measured by photon coincidence detection with a visibility of 0.89(6). The Hong-Ou-Mandel interference witnesses an entangled NOON state of the collective atomic excitations, and we demonstrate its two times enhanced sensitivity to a magnetic field compared with a single excitation. Our work implements a minimal instance of boson sampling and paves the way for further multimode and multiexcitation studies with collective excitations of atomic ensembles.
We summarize our recent work on quantum information with atomic ensembles. In particular, we describe techniques for storing and manipulating quantum information in collective states of mesoscopic ensembles. Quantum information processing is is accomplished by optical excitation into states with strong dipole-dipole interactions. The resulting “dipole blockade” can be used to inhibit transitions into all but singly excited collective states. This can be employed for a controlled generation of collective atomic spin states as well as non-classical photonic states and for scalable quantum logic gates. Furthermore, we present schemes for entangling a very large number of atoms of a spinor 1 Bose Einstein condensate based on collisional interaction between atoms. As a final example, we discuss the possiblilty of creating entangled atomic states of a few bosonic atoms in a setup which mimics a “fractional quantum Hall effect” and allows the manipulation of anyonic excitations.
The spin state of an atomic ensemble can be viewed as two bosonic modes, i.e., a quantum signal mode and a ccc-numbered ``local oscillator'' mode when large numbers of spin-1/2 atoms are spin polarized along a certain axis and collectively manipulated within the vicinity of the axis. We present a concrete procedure, which determines the spin-excitation-number distribution, i.e., the diagonal elements of the density matrix in the Dicke basis for the collective spin state. By seeing the collective spin state as a statistical mixture of the inherently entangled Dicke states, the physical picture of its multiparticle entanglement is made clear.
Summary form only given. A new approach to the problem of the quantum interface between light and atoms has been recently developed. The method utilizes free space dispersive interaction between pulses of light and spin polarized atomic ensembles. Entanglement between the polarization state of light and the collective spin state of atoms is established by measurement, more precisely by detection of light in a certain polarization basis. In the first demonstration of this approach we have generated a long-lived entangled state of two separate macroscopic atomic samples by a polarization measurement on light transmitted through the samples. We then have shown that this approach also works for mapping of a quantum state of light onto long-lived atomic spin state paving the road towards realization of the quantum memory for light. Recently we have also extended the free space light-atoms interface beyond the continuous variables in the proposal, where a coherent superposition "cat" state of an atomic ensemble is generated by a measurement sequence. Progress with other communication protocols such as atomic state teleportation and multiparty networks will be presented.