High-Resolution Quantum Gas Microscopy of Ultracold 23Na40K Molecules Trapped in Optical Lattices

几十年来，量子计算机有望解决任何经典计算机都无法想象的问题，这一前景一直是物理学家的主要动力，促使他们进一步突破当今的技术界限，努力同时和单独地利用大型粒子集合的量子特性。这些年来，在光子、俘获离子、超冷原子、超导量子比特和最近的马约拉纳费米子等几个平台上取得了重大的概念和技术进步。然而，直到今天，还没有竞争者能够严格地证明量子比经典设备的真正加速。本文提出了一种基于捕获在光学晶格中的超冷偶极23Na40K分子的新型多用途量子硬件。超冷分子代表了一个全新的平台，它借用了超冷原子的技术和可扩展性，并将其与偶极分子的可调远程相互作用相结合。为了在单分子水平上研究和控制相互作用，我们将建立一个分子量子气体显微镜，这仍然是迄今为止一个突出的挑战。实现这种分子量子气体显微镜的难点之一是达到所需的双极双碱分子数量和简并度。这反过来又受到两个超冷原子转化为所谓的费什巴赫分子的效率的限制。本文提出了一种新的途径，通过受激快速绝热通道（STIRAP）将玻色极化子转化为分子，使分子处于旋转振动基态。这种方法有望显著提高转化效率，有可能直接产生超冷分子的简并气体。制作完成后，我们将超冷的23Na40K分子装入单层三维光学晶格中。高分辨率物镜将使我们能够以单点阵位分辨率对分子进行成像，从而为研究具有远程相互作用的各种多体效应打开大门。我们进一步计划通过紧密聚焦的激光束局部控制单个分子的电偶极矩来演示双量子比特门的概念验证实现。控制被困在光学晶格中的简并偶极23Na40K分子的量子性质代表了多用途量子硬件的一个缩影，非常适合量子计算、量子模拟和精确测量。

The promise that quantum computers may solve problems unthinkable for any classical computer has been a leading motivation for physicists over decades to push today’s boundaries of technology further in an effort to harness simultaneously and individually the quantum properties of a large ensemble of particles. During these years, significant conceptual and technological advances have been achieved on several platforms including photons, trapped ions, ultracold atoms, superconducting qubits, and most recently Majorana fermions. However, until the present day no contender has been able to rigorously demonstrate a genuine speedup of quantum over classical devices. We here propose to build a novel multipurpose quantum hardware based on ultracold dipolar 23Na40K molecules trapped in an optical lattice. Ultracold molecules represent a radically new platform which borrows the techniques and scalability from ultracold atoms and combines it with the tunable long-range interactions of dipolar molecules. To study and control the interactions at the single molecule level we will build a molecular quantum gas microscope which remains – so far – an outstanding challenge. One of the difficulties in realizing such a molecular quantum gas microscope is to reach the required number and degeneracy of dipolar bi-alkali molecules. This in turn is limited by the efficiency at which two ultracold atoms can be converted into a so-called Feshbach molecule. We here propose a new pathway of creating molecules in their rovibrational ground state by converting Bose polarons into molecules through a stimulated rapid adiabatic passage (STIRAP). This approach holds promise to significantly enhance the conversion efficiency, potentially allowing the direct creation of a degenerate gas of ultracold molecules. After creation, we will load the ultracold 23Na40K molecules into a single layer of a three-dimensional optical lattice. A high-resolution objective will enable us to image the molecules with single lattice site resolution, thereby opening the doors to study a variety of many-body effects with long-range interaction. We further plan to demonstrate a proof of concept realization of a two-qubit gate by locally controlling the electric dipole moment of individual molecules through tightly focused laser beams. Gaining control over the quantum nature of degenerate dipolar 23Na40K molecules trapped in an optical lattice represents an epitome of a multipurpose quantum hardware ideally suited for quantum computations, quantum simulations, and precision measurements.