編譯 | 李言
Nature, 2 February 2023, Volume 614 Issue 7946
《自然》2023年2月2日，第614卷，7946期
天文學Astronomy
A high-mass X-ray binary descended from an ultra-stripped supernova
源于極度剝離超新星的高質量x射線雙星
▲ 作者：Noel D. Richardson, Clarissa M. Pavao, Jan J. Eldridge, Herbert Pablo, André-Nicolas Chené, Peter Wysocki, Douglas R. Gies, George Younes & Jeremy Hare
▲ 鏈接：
https://www.nature.com/articles/s41586-022-05618-9
▲ 摘要：
在此，我們展示了最近發現的高質量x射線雙星CPD ?29 2176 (CD ?29 5159; SGR 0755-2933)所具有的演化歷史表明，中子星成分是在極度剝離超新星時期形成的。此雙星的軌道元素在周期和離心率上都與已知軌道周期和離心率的14個Be x射線雙星中的1個相似。
對極度剝離超新星的前身星系統的識別是必要的，因為它們的演化路徑導致了雙中子星系統的形成。雙中子星，如被觀測到有電磁和引力能、能產生千新星GW170817的系統，已知會產生大量的重元素。
▲ Abstract：
Here we show that a recently discovered high-mass X-ray binary, CPD ?29 2176 (CD ?29 5159; SGR 0755-2933), has an evolutionary history that shows the neutron star component formed during an ultra-stripped supernova. The binary has orbital elements that are similar both in period and in eccentricity to 1 of 14 Be X-ray binaries that have known orbital periods and eccentricities. The identification of the progenitors systems for ultra-stripped supernovae is necessary as their evolution pathways lead to the formation of binary neutron star systems. Binary neutron stars, such as the system that produced the kilonova GW170817 that was observed with both electromagnetic and gravitational energy, are known to produce a large quantity of heavy elements.
物理學Physics
Field-linked resonances of polar molecules
極性分子的場關聯共振
▲ 作者：Xing-Yan Chen, Andreas Schindewolf, Sebastian Eppelt, Roman Bause, Marcel Duda, Shrestha Biswas, Tijs Karman, Timon Hilker, Immanuel Bloch & Xin-Yu Luo
▲ 鏈接：
https://www.nature.com/articles/s41586-022-05651-8
▲ 摘要：
在此，我們展示了一種適用于廣泛范圍的新型極性分子。所謂的場聯共振發生在微波修飾的分子散射中，因為分子間勢中存在穩定的宏觀四聚體狀態。
我們確定了超冷基態鈉-鉀分子之間的兩種共振，并使用微波頻率和極化將非彈性碰撞率調整為3個數量級，從酉極限到遠低于普遍狀態。
場聯共振提供了一個調諧旋鈕來獨立控制彈性接觸相互作用和偶極子-偶極子相互作用，同時觀察到熱化速率的修正。我們的實驗結果為超冷極性分子之間的共振散射提供了普適的策略，為實現偶極超流體和分子超固體以及組裝超冷多原子分子鋪平了道路。
▲ Abstract：
Here we demonstrate a new type of scattering resonance that is universal for a wide range of polar molecules. The so-called field-linked resonances occur in the scattering of microwave-dressed molecules because of stable macroscopic tetramer states in the intermolecular potential. We identify two resonances between ultracold ground-state sodium–potassium molecules and use the microwave frequencies and polarizations to tune the inelastic collision rate by three orders of magnitude, from the unitary limit to well below the universal regime. The field-linked resonance provides a tuning knob to independently control the elastic contact interaction and the dipole–dipole interaction, which we observe as a modification in the thermalization rate. Our result provides a general strategy for resonant scattering between ultracold polar molecules, which paves the way for realizing dipolar superfluids and molecular supersolids, as well as assembling ultracold polyatomic molecules.
Probing site-resolved correlations in a spin system of ultracold molecules
探測超冷分子自旋系統中的位置分辨相關性
▲ 作者：Lysander Christakis, Jason S. Rosenberg, Ravin Raj, Sungjae Chi, Alan Morningstar, David A. Huse, Zoe Z. Yan & Waseem S. Bakr
▲ 鏈接：
https://www.nature.com/articles/s41586-022-05558-4
▲ 摘要：
在此，我們使用量子氣相顯微鏡來測量限制在二維光學晶格中的極性鈉銣分子的量子相關性的位置分辨動力學。
通過利用分子的2個旋轉狀態，我們實現了粒子之間具有偶極相互作用的自旋1/2系統，產生了量子自旋交換模型。我們研究了空間各向同性和各向異性相互作用的非平衡自旋系統熱化過程中相關關系的演化。
此外，我們利用周期微波脈沖研究了自旋各向異性海森堡模型的相關動力學。這些實驗推動了探測和控制超冷分子相互作用系統的研究前沿，具備探索量子物質新體系和描述量子計算和計量學中有用的糾纏態的前景。
▲ Abstract：
Here we use quantum gas microscopy to measure the site-resolved dynamics of quantum correlations of polar 23Na87Rb molecules confined in a two-dimensional optical lattice. By using two rotational states of the molecules, we realize a spin-1/2 system with dipolar interactions between particles, producing a quantum spin-exchange model. We study the evolution of correlations during the thermalization process of an out-of-equilibrium spin system for both spatially isotropic and anisotropic interactions. Furthermore, we examine the correlation dynamics of a spin-anisotropic Heisenberg model engineered from the native spin-exchange model by using periodic microwave pulses. These experiments push the frontier of probing and controlling interacting systems of ultracold molecules, with prospects for exploring new regimes of quantum matter and characterizing entangled states that are useful for quantum computation and metrology.
A Feshbach resonance in collisions between triplet ground-state molecules
三重態基態分子碰撞中的費希巴赫共振
▲ 作者：Juliana J. Park, Yu-Kun Lu, Alan O. Jamison, Timur V. Tscherbul & Wolfgang Ketterle
▲ 鏈接：
https://www.nature.com/articles/s41586-022-05635-8
▲ 摘要：
在此，我們報告一個在2個三重態基態鈉鋰分子碰撞中的非常明顯且狹窄（25?mG）的費希巴赫共振。
這種分子費希巴赫共振有兩個特殊的特征。第一，由于化學反應性強，碰撞損失率比背景損失率提高了兩個數量級以上，背景損失率在p波普遍值處飽和。第二，共振位于兩個開放通道幾乎退化的磁場中。這意味著中間復合體主要衰變到第二開放通道。
我們使用類似于法布里-珀羅諧振腔的耦合模式模型來描述諧振損耗特征。我們的觀察為即使在沒有反應障礙的系統中也存在長時間相干的中間配合物提供了有力證據，并為化學反應的相干控制帶來了可能性。
▲ Abstract：
Here we report a very pronounced and narrow (25?mG) Feshbach resonance in collisions between two triplet ground-state NaLi molecules. This molecular Feshbach resonance has two special characteristics. First, the collisional loss rate is enhanced by more than two orders of magnitude above the background loss rate, which is saturated at the p-wave universal value, owing to strong chemical reactivity. Second, the resonance is located at a magnetic field where two open channels become nearly degenerate. This implies that the intermediate complex predominantly decays to the second open channel. We describe the resonant loss feature using a model with coupled modes that is analogous to a Fabry–Pérot cavity. Our observations provide strong evidence for the existence of long-lived coherent intermediate complexes even in systems without reaction barriers and open up the possibility of coherent control of chemical reactions.
材料科學Materials Science
Vertical full-colour micro-LEDs via 2D materials-based layer transfer
基于二維材料的層轉移技術的全彩垂直Micro LED
▲ 作者：Jiho Shin, Hyunseok Kim, Suresh Sundaram et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-022-05612-1
▲ 摘要：
在此，我們報告了已知范圍內最高陣列密度（5100像素/英寸）和最小尺寸（4微米）的全彩色垂直堆疊μLEDs。這是通過基于二維材料的層轉移技術實現的，該技術允許在二維材料涂層基片上通過遠程外延或范德華外延、機械釋放和堆疊LED等工序來生長近亞微米厚度的RGB LEDs。
有史以來最小的、約9微米的堆疊高度是制造高陣列密度LED的關鍵因素。我們還演示了藍色μLEDs與硅膜晶體管的垂直集成，可用于有源矩陣應用。這些研究結果為制造用于增強現實和虛擬現實的全彩Micro LED顯示器奠定了基礎，同時也為更廣泛的三維集成設備類別提供了通用平臺。
▲ Abstract：
Here we report full-colour, vertically stacked μLEDs that achieve, to our knowledge, the highest array density (5,100?pixels per inch) and the smallest size (4?μm) reported to date. This is enabled by a two-dimensional materials-based layer transfer technique that allows the growth of RGB LEDs of near-submicron thickness on two-dimensional material-coated substrates via remote or van der Waals epitaxy, mechanical release and stacking of LEDs, followed by top-down fabrication. The smallest-ever stack height of around 9?μm is the key enabler for record high μLED array density. We also demonstrate vertical integration of blue μLEDs with silicon membrane transistors for active matrix operation. These results establish routes to creating full-colour μLED displays for augmented and virtual reality, while also offering a generalizable platform for broader classes of three-dimensional integrated devices.
Non-epitaxial single-crystal 2D material growth by geometric confinement
通過幾何限域實現非外延單晶二維材料生長
▲ 作者：Ki Seok Kim, Doyoon Lee, Celesta S. Chang, Seunghwan Seo, Yaoqiao Hu et al.
▲ 鏈接：
https://www.nature.com/articles/s41586-022-05524-0
▲ 摘要：
在此，我們介紹了一種確定性的限域生長技術，可以同時解決三個問題，從而在任意襯底上獲得晶圓規模的單疇2D單層陣列及其異質結。我們通過在兩英寸襯底上的SiO2掩膜圖案定義一個選擇性生長區域，從幾何上限制了第一組晶核的生長。
由于在微米級SiO2溝槽上的生長時間大大縮短，我們在引入第二組晶核之前，通過第一組晶核的短時間生長來填充溝槽，從而無需外延晶種，在任意基底上獲得了晶圓規模的單疇單層WSe2陣列。
用同樣的原理進一步生長過渡金屬二鹵族化合物，形成單疇MoS2/WSe2異質結。我們的成果將為二維材料適應工業環境奠定堅實基礎。
▲ Abstract：
Here we introduce a deterministic, confined-growth technique that can tackle these three issues simultaneously, thus obtaining wafer-scale single-domain 2D monolayer arrays and their heterostructures on arbitrary substrates. We geometrically confine the growth of the first set of nuclei by defining a selective growth area via patterning SiO2 masks on two-inch substrates. Owing to substantial reduction of the growth duration at the micrometre-scale SiO2 trenches, we obtain wafer-scale single-domain monolayer WSe2 arrays on the arbitrary substrates by filling the trenches via short growth of the first set of nuclei, before the second set of nuclei is introduced, thus without requiring epitaxial seeding. Further growth of transition metal dichalcogenides with the same principle yields the formation of single-domain MoS2/WSe2 heterostructures. Our achievement will lay a strong foundation for 2D materials to fit into industrial settings.
