We analyse a protocol of quantum energy teleportation that transports energy from the left edge of a linear ion crystal to the right edge by local operations and classical communication at a speed considerably greater than the speed of a phonon in the crystal. A probe qubit is strongly coupled with phonon fluctuation in the ground state for a short time, and it is projectively measured in order to obtain information about this phonon fluctuation. During the measurement process, phonons are excited by the time-dependent measurement interaction, and the energy of the excited phonons must be infused from outside the system. The obtained information is transferred to the right edge of the crystal through a classical channel. Even though the phonons excited at the left edge do not arrive at the right edge at the same time as when the information arrives at the right edge, we are able to soon extract energy from the ions at the right edge by using the transferred information. Because the intermediate ions of the crystal are not excited during the execution of the protocol, energy is transmitted in the energy transfer channel without heat generation.
Scaling roadmap for modular trapped-ion QEC and lattice-surgery teleportation
Instituto de Física Teórica UAM-CSIC, Universidad Autónoma de Madrid（马德里自治大学理论物理研究所）；Institute for Quantum Electronics, ETH Zürich（苏黎世联邦理工学院量子电子学研究所）；School of Electrical and Computer Engineering, Cornell University（康奈尔大学电气与计算机工程学院）；Universität Innsbruck, Institut für Experimentalphysik（因斯布鲁克大学实验物理研究所）；Institute for Quantum Information, RWTH Aachen University（亚琛工业大学量子信息研究所）；Institute for Theoretical Nanoelectronics (PGI-2), Forschungszentrum Jülich（于利希研究中心理论纳米电子学研究所）
Large-scale quantum computers will require quantum gate operations between widely separated qubits. A method for implementing such operations, known as quantum gate teleportation (QGT), requires only local operations, classical communication, and shared entanglement. We demonstrate QGT in a scalable architecture by deterministically teleporting a controlled-NOT (CNOT) gate between two qubits in spatially separated locations in an ion trap. The entanglement fidelity of our teleported CNOT is in the interval [0.845, 0.872] at the 95% confidence level. The implementation combines ion shuttling wi…
Robust high-fidelity teleportation of an atomic state through the detection of cavity decay
提出了一种基于腔场衰减探测的原子态量子隐形传态方案。利用单光子探测器测量偏振光子的干涉，可以将囚禁在腔中的原子的内部态离散地转移到另一个囚禁在远处腔中的原子上。与S. Bose，P.L. Knight，M.B. Plenio，and V. Vedral [Phys. Rev. Lett. 83，5158（1999）]，我们的隐形传态协议具有几乎统一的高保真度和固有的鲁棒性，例如保真度对原子位置的随机性和检测效率的不敏感性。所有这些有利的特性使得该方案在当前的实验技术下是可行的。
Generating Einstein$\unicode{x2013}$Podolsky$\unicode{x2013}$Rosen correlations for teleporting collective spin states in a two dimensional trapped ion crystal
We propose and demonstrate a scalable scheme for the simultaneous determination of internal and motional states in trapped ions with single-site resolution. The scheme is applied to the study of polaritonic excitations in the Jaynes- Cummings Hubbard model with trapped ions, in which the internal and motional states of the ions are strongly correlated. We observe quantum phase transitions of polaritonic excitations in two ions by directly evaluating their variances per ion site. Our work establishes an essential technological method for large-scale quantum simulations of polaritonic systems.
Invariant-based inverse engineering is an elegant approach to quantum control with corresponding experimental implementations that perform tasks with applications in quantum information processing such as shuttling trapped ions. We build on recent work to generalise invariant-based inverse engineering to control two coupled harmonic oscillators in any number of spatial dimensions. This may be used to perform experimentally relevant tasks such as separation of trapped ions, which is demonstrated numerically, achieving transfer fidelities of over 96% as well as low motional number excitations.
Essentially all known quantum gates rely on a weak-coupling approximation resulting in linear dynamics. With the explicit example of trapped ions, we show how high-fidelity quantum gates can be achieved outside such an approximation, and we derive readily implementable driving fields to realize gates with extremely high fidelities for ions well outside the Lamb-Dicke regime with motional temperatures achievable by only Doppler cooling.
Simulation of Jahn-Teller-Dicke Magnetic Structural Phase Transition with Trapped Ions
本文从理论上研究了囚禁离子系统中的集体E $\otimes$ e Jahn-Teller-Dicke畸变。我们的重点是在无限范围内的相互作用，其中有效自旋系综与两个集体振动模式与U（1）对称耦合的限制。我们的模型是完全可解的结晶极限，它是适合于解决一个中等数量的离子的精确数值对角化。我们发现，被困离子是理想的适合研究出现的连续对称性和磁结构相变在介观系统的自发对称性破缺。
We apply estimation theory to a system formed by two interacting trapped ions. By using the Fisher matrix formalism, we introduce a simple scheme for estimation of the temperature of the longitudinal vibrational modes of the ions. We use the ions interaction to effectively infer the temperature of the individual ions, by optimising the interaction time evolution and by measuring only over one of the ions. We also investigate the effect of a non-thermal reservoir over the inference approach. The non-classicality of one of the ions vibrational modes, introduced due to a squeezed thermal reservoi…
We have experimentally observed the dynamics of a single polariton and two polaritons in a two-ion chain. By driving two trapped ions at a motional blue-sideband transition, we realize the anti-Jaynes-Cummings-Hubbard model. When a single polariton exists in a trapped-ion chain, the polariton hops between the ion sites. On the other hand, when there are single polaritons at each ion site, the hopping of the polaritons is suppressed because of the polariton-polariton interaction induced by the nonlinearity of the anti-Jaynes-Cummings interaction, thereby realizing the blockade of polariton hopp…
