It is proposed that nuclear (or electron) spins in a trapped molecule would be well isolated from the environment and the state of each spin can be measured by means of mechanical detection of magnetic resonance. Therefore molecular traps make an entirely new approach possible for spin-resonance quantum computation which can be conveniently scaled up. In the context of magnetic resonance spectroscopy, a molecular trap promises the ultimate sensitivity for single spin detection and an unprecedented spectral resolution as well.
Resonance energy transfer between chiral molecules can be used to discriminate between different enantiomers. The transfer rate between chiral molecules consists of a non-discriminatory and discriminatory parts. We derive these two rate contributions in the framework of macroscopic quantum electrodynamics. We show that their ratio is usually larger in the retarded regime or far-zone of large separation distances and that the degree of discrimination can be modified when considering a surrounding medium. We highlight the importance of local field effects onto the degree of discrimination and pr…
We perform a short review of the history of quantum mechanics, with a focus on the historical problems with describing ionization theoretically in the context of quantum mechanics. The essentials of the theory of resonances are presented. The exterior complex scaling method for obtaining resonance parameters within the context of the Schrodinger equation is detailed. We explain how this is implemented for a numerical solution using a finite element method for the scaled variable. Results for the resonance parameters of a one-dimensional hydrogen model in an external direct current (DC) electri…
Scattering resonances are an essential tool for controlling interactions of ultracold atoms and molecules. However, conventional Feshbach scattering resonances, which have been extensively studied in various platforms, are not expected to exist in most ultracold polar molecules due to the fast loss that occurs when two molecules approach at a close distance. Here, we demonstrate a new type of scattering resonances that is universal for a wide range of polar molecules. The so-called field-linked resonances occur in the scattering of microwave-dressed molecules due to stable macroscopic tetramer…
The spintronic properties of magnetic molecules have attracted significant scientific attention. Special emphasis has been placed on the qubit for quantum information processing. The single molecule magnet, bis(phthalocyaninato (Pc)) Tb(III) (TbPc2), is one of the best examined cases in which the delocalized π-radical electron spin of the Pc ligand plays the key role in reading and intermediating the localized Tb spin qubits. We utilized the electron spin resonance (ESR) technique implemented on scanning tunneling microscope (STM) and use it to measure local ESR of single TbPc2 molecule decoup…
Collisional resonances are an important tool which has been used to modify interactions in ultracold gases, for realizing novel Hamiltonians in quantum simulations, for creating molecules from atomic gases and for controlling chemical reactions. So far, such resonances have been observed for atom-atom collisions, atom-molecule collisions and collisions between Feshbach molecules which are very weakly bound. Whether such resonances exist for ultracold ground state molecules has been debated due to the possibly high density of states and/or rapid decay of the resonant complex. Here we report a v…
A partial-wave method is developed to deal with small molecules dominated by a central atom as an extension of earlier single-center methods. In particular, a model potential for the water molecule is expanded over a basis of spherical harmonics. A finite element method is employed to generate local polynomial functions in subintervals over a finite range for the radial variable. The angular parts of the system are represented by spherical harmonics. The problem of Stark resonances is treated with the exterior complex scaling method which incorporates a wavefunction discontinuity at the scalin…
Direct probe of anisotropy in atom-molecule collisions via quantum scattering resonances
各向异性是粒子相互作用的基本性质。它在冷和超冷分子过程中占据核心作用，其中已经发现长程力显著依赖于超冷极性分子碰撞中的取向。最近的实验表明，出现的量子现象，如散射共振在冷碰撞制度由于量子化的分子间的自由度。虽然这些状态已被证明是敏感的相互作用的细节，各向异性的量子共振的影响，迄今为止，逃避实验观察。在这里，我们通过改变分子内部转子的量子态，利用量子共振直接测量原子-分子相互作用的各向异性。我们观察到，只有当分子受到旋转激发时，分子氢与亚稳态氦的潘宁电离才会出现碰撞能量为$k_B$ x 270 mK的量子散射共振。我们使用最先进的从头算和多通道量子分子动力学计算表明，各向异性有助于有效的相互作用，只有$H_2$分子在第一激发旋转状态，而旋转基态$H_2$相互作用纯粹各向同性与亚稳态氦。控制内部分子旋转的量子态，使我们能够打开或关闭各向异性，从而解开相互作用的各向同性和各向异性部分。这些量子现象为最先进的理论描述提供了一个具有挑战性的基准，突出了使用冷碰撞来推进粒子相互作用的微观理解的优势。
Electric-field-controlled Förster resonance energy transfer (FRET) between Rydberg helium (He) atoms and ground-state ammonia (NH$_3$) molecules has been studied at translational temperatures below 100 mK. The experiments were performed in an intrabeam collision apparatus with pulsed supersonic beams of NH$_3$ seeded in He. A range of Förster resonances, between triplet Rydberg states in He with principal quantum numbers of 38, 39 and 40, and the inversion intervals in NH$_3$ were investigated. Resonance widths as low as $100\pm20$ MHz were observed for Rydberg-Rydberg transitions with electri…
