Reply to Folman’s Comment on my publication: A simple, practical experiment to investigate atomic wavefunction reduction within a Stern-Gerlach magnet.

We revisit multi-slit diffraction with a scaling of space and time to exploit an equivalence of wave packets describing quantum free and harmonic oscillator (HO) motion. We introduce a co-moving frame of space and time coordinates to define an effective, time-independent, HO potential that confines and directs initially displaced wave packets along the classical phase space of the oscillator. $N$-slit diffraction in the lab frame from the slits to a distant detector and the familiar spreading of the propagating wave front is then described as the propagation of HO wave packets over just a quarter cycle of the oscillator and confined to the HO potential well. This connection with the co-moving frame suggests a simplified time of flight experiment wherein the arrival time distribution of diffracted particles hitting a \emph{single point detector} in the lab frame images in the co-moving frame as the \emph{full} diffraction pattern from grating to detector.

For free propagation from a focus the Hermite-Gauss wave functions of optics spread in space. In quantum mechanics the Hermite-Gauss functions are referred to as the harmonic oscillator eigen- functions. These functions are used here to describe the interference of wave packets. It has been shown that when transformed to a frame moving with the normal to the wave front trajectories, the Hermite-Gauss functions are constant up to a phase factor which is the Gouy phase. The Gouy phase itself assumes the role of proper space or time coordinate. Along the whole of such a trajectory, the space wave function is proportional to the wave number function. An arbitrary normalisable wave packet can be expanded using the Hermite-Gauss functions as a basis. As example, it is shown that in the co-moving frame, a displaced Gaussian does not spread but rather becomes a coherent state. This allows a particularly simple representation of the Young's interference pattern from two or more slits.

Solvation, the result of the complicated interplay between solvent-solute and solvent-internal interactions, is one of the most important chemical processes. Consequently, a complete theoretical understanding of solvation seems a heroic task. However, it is possible to elucidate fundamental solvation mechanisms by looking into simpler systems, such as ion solvation in atomic baths. In this work, we study ion solvation by calculating the ground state properties of a single ion in a neutral bath from the high-density regime to the low-density regime, finding common ground for these two, in principle, disparate regimes. Our results indicate that a single $^{174}$Yb$^+$ ion in a bath of $^{7}$Li atoms forms a coordination complex at high densities with a coordination number of 8, with strong electrostriction, characteristic of the snowball effect. On the contrary, treating the atomic bath as a dilute quantum gas at low densities, we find that the short range of the ion-atom interaction plays a significant role in the physics of many-body bound states and polarons. Furthermore, in this regime, we explore the role of a putative ion trap, which drastically affects the binding mechanism of the ion and atoms from a quantum gas. Therefore, our results give a novel insight into the universality of ion-neutral systems in the ultracold regime and the possibilities of observing exotic many-body effects.

Predictive control over the selectivity outcome of an organic synthetic method is an essential hallmark of reaction success. Electricity-driven synthesis offers a reemerging approach to facilitate the design of reaction sequences towards increased molecular complexity. In addition to the desirable sustainability features of electroorganic processes, the inherent interfacial nature of electrochemical systems present unique opportunities to tune reaction selectivity. To illustrate this feature, we outline examples of mechanism-guided interfacial control over CO2 electroreduction selectivity, a well-studied and instructive electrochemical process with multiple reduction products that are thermodynamically accessible. These studies reveal how controlled proton delivery to the electrode surface and substrate electroadsorption with the electrode dictate reaction selectivity. We describe and compare simple, yet salient, examples from the electroorganic literature, where we postulate that similar effects predominate the observed reactivity. This perspective highlights how the interface serves as a tunable dimension in electrochemical processes, delineating unique tools to study, manipulate, and achieve reaction selectivity in electricity-driven organic synthesis.

Global mRNA translation may differ dramatically between progenitor cells and their differentiated progeny. One way cell type-specific translation is established is through ribosome concentration. In addition to addressing unique metabolic needs, changes in ribosome concentration may influence cell fate. The mechanisms that determine ribosome abundance in progenitors versus differentiated progeny are not fully understood. Here we investigated this process by focusing on ribosomal RNA (rRNA) synthesis in Drosophila neural progenitors and neurons. We found that rRNA synthesis is robust in neural progenitors but is limited in post-mitotic neurons. Newly born neurons inherit rRNA from their progenitor parent and this inherited rRNA is sufficient for protein synthesis in neurons. Our findings support a model in which neuron-specific translation programs are established by rRNA inheritance.

Neutral zinc-air batteries (ZABs) are promising candidates for the next-generation power devices with considerably elongated lifetime comparing to conventional alkaline ZABs. However, neutral cathodic oxygen reduction reaction is seriously limited by the mass transfer efficiency of hydroxyl due to insufficient interfacial chemical potential-gradient between catalytic layer and electrolyte. Herein, we highlight that electrochemical oxidation induced surface microenvironment optimization could realize optimal chemical potential-gradient around catalytic sites and bring outstanding neutral ORR activity. The electro-deposited sub-nano Pt decorated surface-microenvironment-optimized Co2N samples (denoted as Pt-SMO-Co2N NWs) possessed 92 mV and 365 mV lower overpotential than commercial Pt/C and pristine Co2N in 0.2 M PBS. As for neutral ZABs, Pt-SMO-Co2N NWs cathode delivers a power density of 67.9 mW*cm−2 and displays negligible decay after nearly 80 hours stability test at 20 mA*cm-2. In depth characterization proposes that remarkable performance improvement originates from optimized microenvironment which increases the surface chemical potential gradient and facilitates proton coupled electron transfer during ORR. We anticipated that such synergetic optimization of microenvironment and intrinsic activity of active sites is an effective strategy which may be extended the catalytic reactions beyond ORR.