Dipolar quantum solids emerging in a Hubbard quantum simulator.

In quantum mechanical many-body systems, long-range and anisotropic interactions promote rich spatial structure and can lead to quantum frustration, giving rise to a wealth of complex, strongly correlated quantum phases1. Long-range interactions play an important role in nature; however, quantum simulations of lattice systems have largely not been able to realize such interactions. A wide range of efforts are underway to explore long-range interacting lattice systems using polar molecules2-5, Rydberg atoms2,6-8, optical cavities9-11 or magnetic atoms12-15. Here we realize novel quantum phases in a strongly correlated lattice system with long-range dipolar interactions using ultracold magnetic erbium atoms. As we tune the dipolar interaction to be the dominant energy scale in our system, we observe quantum phase transitions from a superfluid into dipolar quantum solids, which we directly detect using quantum gas microscopy with accordion lattices. Controlling the interaction anisotropy by orienting the dipoles enables us to realize a variety of stripe-ordered states. Furthermore, by transitioning non-adiabatically through the strongly correlated regime, we observe the emergence of a range of metastable stripe-ordered states. This work demonstrates that novel strongly correlated quantum phases can be realized using long-range dipolar interactions in optical lattices, opening the door to quantum simulations of a wide range of lattice models with long-range and anisotropic interactions.

On the origins of life's homochirality: Inducing enantiomeric excess with spin-polarized electrons.

Life as we know it is homochiral, but the origins of biological homochirality on early Earth remain elusive. Shallow closed-basin lakes are a plausible prebiotic environment on early Earth, and most are expected to have significant sedimentary magnetite deposits. We hypothesize that ultraviolet (200- to 300-nm) irradiation of magnetite deposits could generate hydrated spin-polarized electrons sufficient to induce enantioselective prebiotic chemistry. Such electrons are potent reducing agents that drive reduction reactions where the spin polarization direction can enantioselectively alter the reaction kinetics. Our estimate of this chiral bias is based on the strong effective spin-orbit coupling observed in the chiral-induced spin selectivity (CISS) effect, as applied to energy differences in reduction reactions for different isomers. In the original CISS experiments, spin-selective electron transmission through a monolayer of double-strand DNA molecules is observed at room temperature-indicating a strong coupling between molecular chirality and electron spin. We propose that the chiral symmetry breaking due to the CISS effect, when applied to reduction chemistry, can induce enantioselective synthesis on the prebiotic Earth and thus facilitate the homochiral assembly of life's building blocks.

The central dogma of biological homochirality: How does chiral information propagate in a prebiotic network?

Biological systems are homochiral, raising the question of how a racemic mixture of prebiotically synthesized biomolecules could attain a homochiral state at the network level. Based on our recent results, we aim to address a related question of how chiral information might have flowed in a prebiotic network. Utilizing the crystallization properties of the central ribonucleic acid (RNA) precursor known as ribose-aminooxazoline (RAO), we showed that its homochiral crystals can be obtained from its fully racemic solution on a magnetic mineral surface due to the chiral-induced spin selectivity (CISS) effect [Ozturk et al., arXiv:2303.01394 (2023)]. Moreover, we uncovered a mechanism facilitated by the CISS effect through which chiral molecules, such as RAO, can uniformly magnetize such surfaces in a variety of planetary environments in a persistent manner [Ozturk et al., arXiv:2304.09095 (2023)]. All this is very tantalizing because recent experiments with tRNA analogs demonstrate high stereoselectivity in the attachment of L-amino acids to D-ribonucleotides, enabling the transfer of homochirality from RNA to peptides [Wu et al., J. Am. Chem. Soc. 143, 11836 (2021)]. Therefore, the biological homochirality problem may be reduced to ensuring that a single common RNA precursor (e.g., RAO) can be made homochiral. The emergence of homochirality at RAO then allows for the chiral information to propagate through RNA, then to peptides, and ultimately through enantioselective catalysis to metabolites. This directionality of the chiral information flow parallels that of the central dogma of molecular biology-the unidirectional transfer of genetic information from nucleic acids to proteins [F. H. Crick, in Symposia of the Society for Experimental Biology, Number XII: The Biological Replication of Macromolecules, edited by F. K. Sanders (Cambridge University Press, Cambridge, 1958), pp. 138-163; and F. Crick, Nature 227, 561 (1970)].

Origin of biological homochirality by crystallization of an RNA precursor on a magnetic surface.

Homochirality is a signature of life on Earth, yet its origins remain an unsolved puzzle. Achieving homochirality is essential for a high-yielding prebiotic network capable of producing functional polymers like RNA and peptides on a persistent basis. Because of the chiral-induced spin selectivity effect, which established a strong coupling between electron spin and molecular chirality, magnetic surfaces can act as chiral agents and be templates for the enantioselective crystallization of chiral molecules. Here, we studied the spin-selective crystallization of racemic ribo-aminooxazoline (RAO), an RNA precursor, on magnetite (Fe3O4) surfaces, achieving an unprecedented enantiomeric excess (ee) of about 60%. Following the initial enrichment, we then obtained homochiral (100% ee) crystals of RAO after a subsequent crystallization. Our results demonstrate a prebiotically plausible way of achieving system-level homochirality from completely racemic starting materials, in a shallow-lake environment on early Earth where sedimentary magnetite deposits are expected to be common.

Chirality-induced avalanche magnetization of magnetite by an RNA precursor.

Homochirality is a hallmark of life on Earth. To achieve and maintain homochirality within a prebiotic network, the presence of an environmental factor acting as a chiral agent and providing a persistent chiral bias to prebiotic chemistry is highly advantageous. Magnetized surfaces are prebiotically plausible chiral agents due to the chiral-induced spin selectivity (CISS) effect, and they were utilized to attain homochiral ribose-aminooxazoline (RAO), an RNA precursor. However, natural magnetic minerals are typically weakly magnetized, necessitating mechanisms to enhance their magnetization for their use as effective chiral agents. Here, we report the magnetization of magnetic surfaces by crystallizing enantiopure RAO, whereby chiral molecules induce a uniform surface magnetization due to the CISS effect, which spreads across the magnetic surface akin to an avalanche. Chirality-induced avalanche magnetization enables a feedback between chiral molecules and magnetic surfaces, which can amplify a weak magnetization and allow for highly efficient spin-selective processes on magnetic minerals.