Experimental long-lived entanglement of two macroscopic objects

By B. Julsgaard, A. Kozhekin, Eugene Simon Polzik. Nature, 2001

949 citations recorded by the source corpus.

Entanglement is considered to be one of the most profound features of quantum mechanics. An entangled state of a system consisting of two subsystems cannot be described as a product of the quantum states of the two subsystems. In this sense, the entangled system is considered inseparable and non-local. It is generally believed that entanglement is usually manifest in systems consisting of a small number of microscopic particles. Here we demonstrate experimentally the entanglement of two macroscopic objects, each consisting of a caesium gas sample containing about 1012 atoms. Entanglement is generated via interaction of the samples with a pulse of light, which performs a non-local Bell measurement on the collective spins of the samples. The entangled spin-state can be maintained for 0.5 milliseconds. Besides being of fundamental interest, we expect the robust and long-lived entanglement of material objects demonstrated here to be useful in quantum information processing, including teleportation of quantum states of matter and quantum memory.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/736f2cbb493687c0cd08f7648ef070dc76b911bb

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Citations in the corpus

Colloquium: Trapping and manipulating photon states in atomic ensembles (2003, background): “Recently these ideas have led to the striking experimental demonstration of entanglement of two macroscopic samples of atoms (Julsgaard et al., 2001).”
Exponential Improvement in Photon Storage Fidelities Using Subradiance and “Selective Radiance” in Atomic Arrays (2017, background): “Atomic ensembles have enabled a number of spectacular proof-of-principle demonstrations of quantum protocols, such as coherent photon storage and quantum memories for light [1–3], entanglement generation between light and atomic spins [4], nonlinear interactions between photons at the level of indiv”
Quantum metrology with nonclassical states of atomic ensembles (2016, methodology): “ated between spatially separated atomic vapor cells using a measurement-based scheme (Julsgaard et al., 2001).”
Quantum repeaters based on atomic ensembles and linear optics (2009, positive): “…demonstrating the storage and teleportation of quantum continuous variables of light in atomic ensembles performed with homodyne detection, e.g. (Appel et al., 2008; Cviklinski et al., 2008; Honda et al., 2008; Julsgaard et al., 2001, 2004; Sherson et al., 2006) will not be discussed here.”