Decoherence-Free Interaction between Giant Atoms in Waveguide Quantum Electrodynamics
Decoherence-Free Interaction between Giant Atoms in Waveguide Quantum Electrodynamics
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DOI：
10.1103/physrevlett.120.140404
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发表时间：
2018-04-05
影响因子：
8.6
通讯作者：
Nori, Franco
中科院分区：
文献类型：
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作者：
Kockum, Anton Frisk;Johansson, Goran;Nori, Franco
在使用天然和人造原子的量子光学实验中，原子通常足够小，与它们相互作用的电磁辐射的波长相比，它们可以近似为点状。然而，超导量子比特耦合到曲折的传输线，或表面声波，可以实现“巨大的人造原子”，耦合到玻色子场在几个点，波长分开。在这里，我们研究了多个巨原子在多个点耦合到一维（1D）波导的设置。我们发现，巨原子可以通过波导保护从散相干，但仍然有交换相互作用介导的波导。与无退相干子空间不同，这里整个多原子希尔伯特空间（N个原子的2（N）个态）被保护不受退相干的影响。这对于“小”原子来说是不可能的。我们进一步展示了如何在具有多个原子的设置中设计这种无消相干的相互作用，以实现，例如，具有最近邻耦合的一维原子链或具有全对全连接性的原子集合。这可能在量子模拟和量子计算中有重要的应用。
In quantum-optics experiments with both natural and artificial atoms, the atoms are usually small enough that they can be approximated as pointlike compared to the wavelength of the electromagnetic radiation with which they interact. However, superconducting qubits coupled to a meandering transmission line, or to surface acoustic waves, can realize "giant artificial atoms" that couple to a bosonic field at several points which are wavelengths apart. Here, we study setups with multiple giant atoms coupled at multiple points to a one-dimensional (1D) waveguide. We show that the giant atoms can be protected from decohering through the waveguide, but still have exchange interactions mediated by the waveguide. Unlike in decoherence-free subspaces, here the entire multiatom Hilbert space (2(N) states for N atoms) is protected from decoherence. This is not possible with "small" atoms. We further show how this decoherence-free interaction can be designed in setups with multiple atoms to implement, e.g., a 1D chain of atoms with nearest-neighbor couplings or a collection of atoms with all-to-all connectivity. This may have important applications in quantum simulation and quantum computing.