Estimation of a general time-dependent Hamiltonian for a single qubit.
Estimation of a general time-dependent Hamiltonian for a single qubit.
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DOI：
10.1038/ncomms11218
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发表时间：
2016-04-14
影响因子：
16.6
通讯作者：
Home JP
中科院分区：
文献类型：
--
作者：
de Clercq LE;Oswald R;Flühmann C;Keitch B;Kienzler D;Lo HY;Marinelli M;Nadlinger D;Negnevitsky V;Home JP
封闭量子系统的哈密顿量决定了它的整个时间演化。虽然可以使用各种方法恢复在单个基中具有时间变化的哈密顿量，但对于更一般的哈密顿量，非对易项的存在使重建复杂化。在这里，使用一个单一的被困离子，我们提出并实验证明了一种方法，用于估计一个单一的量子位的时间依赖的哈密顿量。我们在一个固定的基础上测量量子比特的时间演化作为一个与时间无关的偏移项添加到哈密顿量的函数。最初未知的哈密顿量来自于通过静态激光束传输离子。哈密顿估计允许我们估计空间束强度分布和离子速度作为时间的函数。估计技术是足够普遍的，它可以应用于其他量子系统，帮助追求高操作的量子控制的可靠性。 如果变化发生在单个基中，则可以通过实验重建时变哈密顿量，但更一般的情况是复杂的。在这里，作者提出了一种方法来估计一般的含时哈密顿量的一个单一的自旋量子比特，并将其应用到捕获离子通过静态激光束传输。
The Hamiltonian of a closed quantum system governs its complete time evolution. While Hamiltonians with time-variation in a single basis can be recovered using a variety of methods, for more general Hamiltonians the presence of non-commuting terms complicates the reconstruction. Here using a single trapped ion, we propose and experimentally demonstrate a method for estimating a time-dependent Hamiltonian of a single qubit. We measure the time evolution of the qubit in a fixed basis as a function of a time-independent offset term added to the Hamiltonian. The initially unknown Hamiltonian arises from transporting an ion through a static laser beam. Hamiltonian estimation allows us to estimate the spatial beam intensity profile and the ion velocity as a function of time. The estimation technique is general enough that it can be applied to other quantum systems, aiding the pursuit of high-operational fidelities in quantum control. Time-varying Hamiltonians can be reconstructed experimentally if the variation takes place in a single basis, but more general cases are complicated. Here, the authors present an approach to estimate the general time-dependent Hamiltonian of a single spin-qubit and apply it to a trapped-ion transported through a static laser beam.