Partitioning dysprosium's electronic spin to reveal entanglement in non-classical states
| Autor: | Aurélien Fabre, Jean-Baptiste Bouhiron, Raphael Lopes, Sylvain Nascimbene, Tanish Satoor, Alexandre Evrard |
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| Přispěvatelé: | Laboratoire Kastler Brossel (LKB [Collège de France]), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Collège de France (CdF (institution)) |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Physics
Quantum Physics Quantum decoherence Cat state FOS: Physical sciences Quantum entanglement Coupling (probability) 01 natural sciences 010305 fluids & plasmas [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph] Quantum Gases (cond-mat.quant-gas) Qubit Excited state Quantum mechanics 0103 physical sciences W state Quantum Physics (quant-ph) 010306 general physics Ground state Condensed Matter - Quantum Gases ComputingMilieux_MISCELLANEOUS |
| Zdroj: | Physical Review Research Physical Review Research, American Physical Society, 2021, 3 (4), ⟨10.1103/PhysRevResearch.3.043001⟩ |
| ISSN: | 2643-1564 |
| DOI: | 10.1103/PhysRevResearch.3.043001⟩ |
| Popis: | Quantum spins of mesoscopic size are a well-studied playground for engineering non-classical states. If the spin represents the collective state of an ensemble of qubits, its non-classical behavior is linked to entanglement between the qubits. In this work, we report on an experimental study of entanglement in dysprosium's electronic spin. Its ground state, of angular momentum $J=8$, can formally be viewed as a set of $2J$ qubits symmetric upon exchange. To access entanglement properties, we partition the spin by optically coupling it to an excited state $J'=J-1$, which removes a pair of qubits in a state defined by the light polarization. Starting with the well-known W and squeezed states, we extract the concurrence of qubit pairs, which quantifies their non-classical character. We also directly demonstrate entanglement between the 14- and 2-qubit subsystems via an increase in entropy upon partition. In a complementary set of experiments, we probe decoherence of a state prepared in the excited level $J'=J+1$ and interpret spontaneous emission as a loss of a qubit pair in a random state. This allows us to contrast the robustness of pairwise entanglement of the W state with the fragility of the coherence involved in a Schr\"odinger cat state. Our findings open up the possibility to engineer novel types of entangled atomic ensembles, in which entanglement occurs within each atom's electronic spin as well as between different atoms. Comment: 14 pages, 10 figures |
| Databáze: | OpenAIRE |
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