On-chip generation of high-dimensional entangled quantum states and their coherent control
The on-chip generation of high-dimensional frequency-entangled states and their spectral-domain manipulation are demonstrated, introducing a powerful and practical platform for quantum information processing. Entangled qudits for quick communications Qubits, the quantum version of bits, are construc...
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| Veröffentlicht in: | Nature (London) Jg. 546; H. 7660; S. 622 - 626 |
|---|---|
| Hauptverfasser: | , , , , , , , , , , , , , |
| Format: | Journal Article |
| Sprache: | Englisch |
| Veröffentlicht: |
London
Nature Publishing Group UK
29.06.2017
Nature Publishing Group |
| Schlagworte: | |
| ISSN: | 0028-0836, 1476-4687, 1476-4687 |
| Online-Zugang: | Volltext |
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| Zusammenfassung: | The on-chip generation of high-dimensional frequency-entangled states and their spectral-domain manipulation are demonstrated, introducing a powerful and practical platform for quantum information processing.
Entangled qudits for quick communications
Qubits, the quantum version of bits, are constructed from two-level quantum systems, but in principle a quantum information processor could exploit higher-dimensional quantum systems for operation. These systems with an arbitrary number of levels are often termed qudits and can be generated, for example, from photons. Using qudits instead of qubits can increase sensitivity in quantum imaging and can boost quantum communication schemes. Here, Michael Kues
et al
. generate two entangled qudits on an integrated photonic chip using a four-wave mixing process. Each qudit encodes a 10-dimensional state, enabling the realization of a quantum system with 100 dimensions. This technique could find application in fibre-based quantum communications.
Optical quantum states based on entangled photons are essential for solving questions in fundamental physics and are at the heart of quantum information science
1
. Specifically, the realization of high-dimensional states (
D
-level quantum systems, that is, qudits, with
D
> 2) and their control are necessary for fundamental investigations of quantum mechanics
2
, for increasing the sensitivity of quantum imaging schemes
3
, for improving the robustness and key rate of quantum communication protocols
4
, for enabling a richer variety of quantum simulations
5
, and for achieving more efficient and error-tolerant quantum computation
6
. Integrated photonics has recently become a leading platform for the compact, cost-efficient, and stable generation and processing of non-classical optical states
7
. However, so far, integrated entangled quantum sources have been limited to qubits (
D
= 2)
8
,
9
,
10
,
11
. Here we demonstrate on-chip generation of entangled qudit states, where the photons are created in a coherent superposition of multiple high-purity frequency modes. In particular, we confirm the realization of a quantum system with at least one hundred dimensions, formed by two entangled qudits with
D
= 10. Furthermore, using state-of-the-art, yet off-the-shelf telecommunications components, we introduce a coherent manipulation platform with which to control frequency-entangled states, capable of performing deterministic high-dimensional gate operations. We validate this platform by measuring Bell inequality violations and performing quantum state tomography. Our work enables the generation and processing of high-dimensional quantum states in a single spatial mode. |
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| Bibliographie: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 content type line 23 |
| ISSN: | 0028-0836 1476-4687 1476-4687 |
| DOI: | 10.1038/nature22986 |