Neutral two-electron atoms trapped in a programmable optical tweezer array can be locally manipulated by laser fields within a realistic and comprehensive experimental architecture for quantum information processing. The proposed scheme (see article number 1800067 by Guido Pagano et al.) harnesses the nuclear spin and electronic clock degrees of freedom of alkaline-earth-like atoms to afford a fully controllable, robust and scalable quantum processor.
Neutral two-electron atoms trapped in a programmable optical tweezer array can be locally manipulated by laser fields within a realistic and comprehensive experimental architecture for quantum information processing. The proposed scheme (see article number 1800067 by Guido Pagano et al.) harnesses the nuclear spin and electronic clock degrees of freedom of alkaline-earth-like atoms to afford a fully controllable, robust and scalable quantum processor.
Abstract Atomic systems, ranging from trapped ions to ultracold and Rydberg atoms, offer unprecedented control over both internal and external degrees of freedom at the single‐particle level. They are considered among the foremost candidates for realizing quantum simulation and computation platforms that can outperform classical computers at specific tasks. In this work, a realistic experimental toolbox for quantum information processing with neutral alkaline‐earth‐like atoms in optical tweezer arrays is described. In particular, a comprehensive and scalable architecture based on a programmable array of alkaline‐earth‐like atoms is proposed, exploiting their electronic clock states as a precise and robust auxiliary degree of freedom, and thus allowing for efficient all‐optical one‐ and two‐qubit operations between nuclear spin qubits. The proposed platform promises excellent performance thanks to high‐fidelity register initialization, rapid spin‐exchange gates, and error detection in read‐out. As a benchmark and application example, the expected fidelity of an increasing number of subsequent SWAP gates for optimal parameters is computed, which can be used to distribute entanglement between remote atoms within the array.
Neutral atoms trapped by laser light are among the most promising candidates for storing and processing information in a quantum computer or simulator. The application certainly calls for a scalable and flexible scheme for addressing and manipulating the atoms. We have now made this a reality by implementing a fast and versatile method to dynamically control the position of neutral atoms trapped in optical tweezers. The tweezers result from a spatial light modulator (SLM) controlling and shaping a large number of optical dipole-force traps. Trapped atoms adapt to any change in the potential landscape, such that one can rearrange and randomly access individual sites within atom-trap arrays.
Alkaline Atoms Held with Optical TweezersThree separate groups demonstrate the trapping of two-electron atoms in arrays of optical tweezers, opening up new opportunities for quantum simulation and many-body studies.by Antoine Browaeys * Q uantum technology is a very active field of research, in which the resources of quantum physics, such as superposition and entanglement, are utilized to perform tasks that are classically hard or impossible.The promises from this field are many, ranging from quantum computation of difficult mathematical problems to the building of more sensitive sensors.But to realize these possibilities, experimentalists have to engineer well-controlled quantum systems made of many individual elements that can interact with each other.Among the many platforms currently studied (ions, photons, electron spins, to name a few), neutral atoms have the advantage that they can be manipulated with high accuracy, and they are scalable in the sense that many thousands of atoms can be controlled.New experiments by three separate groups have
Neutral atoms trapped in arrays of optical tweezers are a versatile platform for multiple research efforts in quantum information science. In particular, alkaline-earth atoms like Yb offer many advantages including ultralong coherence nuclear spin states for quantum information storage and high-fidelity qubit operations, optical transitions to Rydberg states for generating strong, long-range interactions between atoms, and narrow optical transitions for efficient cooling and metrology. Additionally, optical transitions from the long-lived 3P0 nuclear spin state have frequencies in the telecommunications band making integration with fiber networks and silicon nanophotonics an attractive avenue of exploration for hybrid quantum systems and quantum communication. Finally, these optical tweezer platforms are well suited for investigating the cooperative response of an array of atoms, where the proximity of neighboring atoms fundamentally alters the systems optical response which has implications for quantum information storage. Here I will present efforts to investigate these research avenues using alkaline-earth atoms in optical tweezers.
We report on the realization of a fast, scalable, and high-fidelity qubit architecture, based on 171 Yb atoms in an optical tweezer array.We demonstrate several attractive properties of this atom for its use as a building block of a quantum information processing platform.Its nuclear spin of 1=2 serves as a long-lived and coherent two-level system, while its rich, alkaline-earth-like electronic structure allows for low-entropy preparation, fast qubit control, and high-fidelity readout.We present a near-deterministic loading protocol, which allows us to fill a 10 × 10 tweezer array with 92.73(8)% efficiency and a single tweezer with 96.0(1.4)%efficiency.In the future, this loading protocol will enable efficient and uniform loading of target arrays with high probability, an essential step in quantum simulation and information applications.Employing a robust optical approach, we perform submicrosecond qubit rotations and characterize their fidelity through randomized benchmarking, yielding 5.2ð5Þ × 10 -3 error per Clifford gate.For quantum memory applications, we measure the coherence of our qubits with T Ã 2 ¼ 3.7ð4Þ s and T 2 ¼ 7.9ð4Þ s, many orders of magnitude longer than our qubit rotation pulses.We measure spin depolarization times on the order of tens of seconds and find that this can be increased to the 100 s scale through the application of a several-gauss magnetic field.Finally, we use 3D Raman-sideband cooling to bring the atoms near their motional ground state, which will be central to future implementations of two-qubit gates that benefit from low motional entropy.
Neutral atoms for quantum computing applications show promise in terms of scalability and connectivity. We demonstrate the realization of a versatile apparatus capable of stochastically loading a 5x5 array of optical tweezers with single 88Sr atoms featuring flexible magnetic field control and excellent optical access. A custom-designed oven, spin-flip Zeeman slower, and deflection stage produce a controlled flux of Sr directed to the science chamber. In the science chamber, featuring a vacuum pressure of 3×10−11 mbar, the Sr is cooled using two laser cooling stages, resulting in ∼3×105 atoms at a temperature of 5(1) μK. The optical tweezers feature a 1/e2 waist of 0.81(2) μm, and loaded atoms can be imaged with a fidelity of ∼0.997 and a survival probability of 0.99−0.02+0.01. The atomic array presented here forms the core of a full-stack quantum computing processor targeted for quantum chemistry computational problems.