Papers
Topics
Authors
Recent
Gemini 2.5 Flash
Gemini 2.5 Flash
139 tokens/sec
GPT-4o
7 tokens/sec
Gemini 2.5 Pro Pro
46 tokens/sec
o3 Pro
4 tokens/sec
GPT-4.1 Pro
38 tokens/sec
DeepSeek R1 via Azure Pro
28 tokens/sec
2000 character limit reached

Generation and manipulation of Schrödinger cat states in Rydberg atom arrays (1905.05721v3)

Published 14 May 2019 in quant-ph, cond-mat.quant-gas, and physics.atom-ph

Abstract: Quantum entanglement involving coherent superpositions of macroscopically distinct states is among the most striking features of quantum theory, but its realization is challenging, since such states are extremely fragile. Using a programmable quantum simulator based on neutral atom arrays with interactions mediated by Rydberg states, we demonstrate the deterministic generation of 'Schr\"odinger cat' states of the Greenberger-Horne-Zeilinger (GHZ) type with up to 20 qubits. Our approach is based on engineering the energy spectrum and using optimal control of the many-body system. We further demonstrate entanglement manipulation by using GHZ states to distribute entanglement to distant sites in the array, establishing important ingredients for quantum information processing and quantum metrology.

Citations (494)

Summary

  • The paper presents a method to generate GHZ states with up to 20 qubits in a 1D Rydberg atom array using adiabatic passage and optimal control techniques.
  • It manipulates entanglement by redistributing GHZ states into remote Bell pairs, showcasing potential applications in quantum networking and error correction.
  • The study achieves significant fidelity (≥0.542) for 20-atom states by addressing experimental challenges with advanced calibration and CRAB optimization methods.

Quantum Dynamics in Rydberg Atom Arrays: Creation and Manipulation of Schrödinger Cat States

This paper explores the sophisticated experimental realization of Greenberger-Horne-Zeilinger (GHZ) states, a class of highly entangled quantum states, using arrays of neutral atoms excited to Rydberg states. It outlines methodologies for generating these states with high fidelity and demonstrates the potential for these states in quantum information processing and metrological applications.

Key Contributions

  1. GHZ State Generation: The paper presents a method to generate GHZ states with up to 20 qubits in a one-dimensional array of Rydberg atoms. By utilizing the strong van-der-Waals interaction in the Rydberg states and implementing an optimized energy spectrum control, GHZ states are prepared through adiabatic passage and optimal control techniques.
  2. Entanglement Distribution and Manipulation: Beyond generation, the authors successfully manipulate these GHZ states to redistribute entanglement along the array. Specifically, they illustrate entanglement sharing between distant atom pairs in the array, forming remote Bell states, which highlights the potential for quantum network applications.
  3. Fidelity Analysis: The fidelity of the GHZ states and the related Bell states reached significant values; a lower bound of fidelity was estimated at F0.542(18)\mathcal{F}\geq0.542(18) for the 20-atom GHZ states, an impressive result for systems of this scale. The experimental challenges such as atomic interaction, decoherence, laser phase noise, and detection errors were systematically addressed using optimization algorithms and advanced experimental settings.

Technical Details and Innovations

  • The experiment uses Rydberg blockade, where the proximity of atoms in Rydberg states prevents simultaneous excitations of adjacent atoms, promoting an intricate control over their quantum states.
  • The authors employ the CRAB (Chopped RAndom Basis) optimization technique to tailor pulse profiles for high-fidelity state preparation. The technique dynamically adjusts the Rabi frequency and detuning, accommodating for environmental fluctuations and interatomic interactions.
  • The paper outlines a detailed calibration procedure for detecting and quantifying errors in state detection, critical for state characterization over the large qubit arrays.

Implications and Future Prospects

The research validates Rydberg atom arrays as a formidable platform for quantum simulation, with implications in quantum metrology, networking, and computation. By showcasing complex GHZ state preparation and entanglement manipulation, the authors open avenues for utilizing these entangled states in practical quantum error correction and quantum communication protocols.

Future work could see the scaling of these techniques to larger arrays and integration of ground-state qubit encoding systems to prolong coherence times, facilitating more sophisticated quantum operations. Rydberg states' vast potential in entanglement distribution emphasizes their role in the burgeoning field of quantum networks, particularly in light of recent advancements that resonate with the findings presented here.

This work contributes robustly to the field by advancing neutral atom technologies while addressing pivotal challenges in quantum state control and fidelity, instrumental for the next-generation quantum information systems.