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The ability to prepare non-classical states in a robust manner is essential for quantum sensors beyond the standard quantum limit. We demonstrate that Bayesian optimal control is capable of finding control pulses that drive trapped Rydberg…

Quantum Physics · Physics 2020-11-18 Rick Mukherjee , Harry Xie , Florian Mintert

We present an entanglement scheme for Rydberg atoms using the van der Waals interaction phase induced by Ramsey-type pulsed interactions. This scheme realizes not only controlled phase operations between atoms at a distance larger than…

Atomic Physics · Physics 2020-01-29 Hanlae Jo , Yunheung Song , Minhyuk Kim , Jaewook Ahn

In a neutral atom quantum computer, the qubits are individual neutral atoms trapped in optical tweezers. Excitations to Rydberg states form the basis for the entanglement procedure that is at the basis of multi-qubit quantum gates. However,…

Quantum Physics · Physics 2023-09-11 R. J. P. T. de Keijzer , O. Tse , S. J. J. M. F. Kokkelmans

We propose two semi-device-independent approaches that are able to quantify unknown multipartite quantum entanglement experimentally, where the only information that has to be known beforehand is quantum dimension, and the concept that…

Quantum Physics · Physics 2022-01-05 Lijinzhi Lin , Zhaohui Wei

We obtain criteria for entanglement and the EPR paradox for spin-entangled particles and analyse the effects of decoherence caused by absorption and state purity errors. For a two qubit photonic state, entanglement can occur for all…

Quantum Physics · Physics 2010-09-17 E. G. Cavalcanti , P. D. Drummond , H. A. Bachor , M. D. Reid

The role of electron-nuclear entanglement on the validity of the Born-Oppenheimer (BO) approximation is investigated. While nonadiabatic couplings generally lead to entanglement and to a failure of the BO approximation, surprisingly the…

Quantum Physics · Physics 2016-05-24 Artur F. Izmaylov , Ignacio Franco

The generation of atomic entanglement is discussed in a system that atoms are trapped in separate cavities which are connected via optical fibers. Two distant atoms can be projected to Bell-state by synchronized turning off the local laser…

Quantum Physics · Physics 2009-11-13 Y. Q. Guo , H. Y. Zhong , Y. H. Zhang , H. S. Song

$W$ states are quantum correlated states possessing both bipartite and multipartite entanglement, which makes them useful for several quantum algorithms. We propose a protocol to generate these states by exploiting {\it topological ring…

The so-called state-carving protocol generates high-fidelity entangled states at an atom-cavity interface without requiring high cavity cooperativity. However, this protocol is limited to 50\% efficiency, which restricts its applicability.…

The advent of digital neutral-atom quantum computers relies on the development of fast and robust protocols for high-fidelity quantum operations. In this work, we introduce a novel scheme for entangling gates using four atomic levels per…

Quantum Physics · Physics 2025-07-22 Giuliano Giudici , Stefano Veroni , Giacomo Giudice , Hannes Pichler , Johannes Zeiher

We derive an optimal bound for arbitrary entanglement manipulation based on the transmission of a pulse in coherent states over a lossy channel followed by local operations and unlimited classical communication (LOCC). This stands on a…

Quantum Physics · Physics 2015-05-30 Koji Azuma , Go Kato

We present experimental results on two-qubit Rydberg blockade quantum gates and entanglement in a two-dimensional qubit array. Without post selection against atom loss we achieve a Bell state fidelity of $0.73\pm 0.05$, the highest value…

Quantum Physics · Physics 2015-08-26 K. M. Maller , M. T. Lichtman , T. Xia , Y. Sun , M. J. Piotrowicz , A. W. Carr , L. Isenhower , M. Saffman

Realizing large-scale quantum networks requires the generation of high-fidelity quantum entanglement states between remote quantum nodes, a key resource for quantum communication, distributed computation and sensing applications. However,…

Previous work on Bell's inequality realised in the laboratory has used entangled photons. Here we describe how entangled atoms can violate Bell's inequality, and how these violations can be measured with a very high detection efficiency. We…

Quantum Physics · Physics 2009-11-06 Almut Beige , William J. Munro , Peter L. Knight

We explore the possibilities of creating radiatively stable entangled states of two three-level dipole-interacting atoms in a $\Lambda$ configuration by means of laser biharmonic continuous driving or pulses. We propose three schemes for…

Quantum Physics · Physics 2009-10-31 I. V. Bargatin , B. A. Grishanin , V. N. Zadkov

Qubit reset is a basic prerequisite for operating quantum devices, requiring the export of entropy. The fastest and most accurate way to reset a qubit is obtained by coupling the qubit to an ancilla on demand. Here, we derive fundamental…

We investigate the robustness of two-qubit gates to deviations of experimental controls, on a neutral atom platform utilizing Rydberg states. We construct robust CZ gates - employing techniques from quantum optimal control - that retain…

Quantum Physics · Physics 2023-09-11 Madhav Mohan , Robert de Keijzer , Servaas Kokkelmans

Entanglement represents one of the most important conceptual advances in physics during the last century and is also one of the most essential resources in quantum information science. However, entanglement is fragile and its potential…

We establish a relationship between the correlations in a many-qubit mixed state and the minimum circuit depth needed for its preparation. If the mutual information between two subsystems exceeds the mutual information between one of those…

Quantum Physics · Physics 2025-10-03 Max McGinley , Samuel J. Garratt

A quantum-feedback-based scheme is proposed for generating multipartite entanglements of Rydberg atoms in a dissipative optical cavity. The Rydberg blockade mechanism efficiently prevents double excitations of the system, which is further…

Quantum Physics · Physics 2017-02-15 X. Q. Shao , J. H. WU , X. X. Yi