Classical theories of gravity produce entanglement
经典引力理论孕育发生了量子纠缠
▲作者：Joseph Aziz Richard Howl
▲ 链接：https://www.nature.com/articles/s41586-025-09595-7
▲ 择要：
引力及量子力学的同一仍旧是科学中最深刻的开放性问题之一。随着量子技术的最新进展，理查德 费曼率先提出的一个试验构想现在被认为是初次检验这类同一理论的可行路子。
该试验包罗将一个年夜质量物体置在两个位置的量子叠加态中，并让其与另外一个质量体发生相互作用。如果两个物体随后发生量子纠缠，则被认为是引力遵照量子力学定律的决议性证据。这一结论来历在一些将经典引力相互作用视为只能传输经典信息而非量子信息的局部相互作用的定理。
研究组将这些定理中利用的物资描写符扩大到量子场论的完备框架，发现经典引力理论可以传输量子信息，从而经由历程物理定域历程孕育发生量子纠缠。该效应的标度律与量子引力理论所推测的差异，是以它提供了可强有力证实引气力子性子的试验参数及情势信息。
▲ Abstract：
The unification of gravity and quantum mechanics remains one of the most profound open questions in science. With recent advances in quantum technology, an experimental idea first proposed by Richard Feynman is now regarded as a promising route to testing this unification for the first time. The experiment involves placing a massive object in a quantum superposition of two locations and letting it gravitationally interact with another mass. If the two objects subsequently become entangled, this is considered unambiguous evidence that gravity obeys the laws of quantum mechanics. This conclusion derives from theorems that treat a classical gravitational interaction as a local interaction capable of transmitting only classical, not quantum, information. Here we extend the description of matter used in these theorems to the full framework of quantum field theory, finding that theories with classical gravity can then transmit quantum information and, thus, generate entanglement through physical, local processes. The effect scales differently to that predicted by theories of quantum gravity, and so it gives information on the parameters and form of the experiment required to robustly provide evidence for the quantum nature of gravity.
Deterministic soliton microcombs in Cu-free photonic integrated circuits
无铜光子集成电路中简直定性孤子微梳
▲作者：Xinru Ji, Xurong Li, Zheru Qiu, Rui Ning Wang, Marta Divall, Andrey Gelash, et al.
▲ 链接：https://www.nature.com/articles/s41586-025-09598-4
▲ 择要：
基在微谐振器的芯片级光学频率梳（微梳）可以或许实现GHz到THz重复频率、宽带宽、紧凑形状因子及与晶圆级制造兼容的光频梳。Si3N4光子集成电路作为一个领先的平台，迄今已经用在险些所有体系级演示，从光通讯、并行激光雷达、光频率合成、低噪声微波孕育发生到并行卷积处置处罚。
然而，因为确定性孤子微梳的天生具备很强的热不稳定性，该技术向试验室外现实运用的转化进展迟缓。虽然人们已经经开发了种种各样的技术来引发孤子孕育发生，包罗脉冲泵浦、快速扫描及辅助激光泵浦，但这些技术其实不能消弭热效应，而且往往会经由历程增长特别的繁杂性或者削减可获得的孤子存于规模而侵害微梳性能。
研究组降服了热效应并证实了Si3N4光子集成电路中确定性孤子的天生。他们于波导中追踪到意想不到的铜杂质热效应，这些杂质来自CMOS级硅晶片中的残留污染物，并于制造历程中进入Si3N4。经由历程开发除了铜技术，他们年夜年夜降低了铜浓度，从而按捺了热效应。
研究组证实了肆意激光扫描轮廓及慢速激光扫描下耗散克尔孤子简直定性天生。该技术可直策应用在代工厂Si3N4器件的前端线工艺，为孤子微梳技术的现实运用扫除了要害障碍。
▲ Abstract：
Chip-scale optical frequency combs based on microresonators (microcombs) have provided access to optical combs with GHz-to-THz repetition rates, broad bandwidth, compact form factors and compatibility with wafer-scale manufacturing. Si3N4photonic integrated circuits emerged as a leading platform and have been used in nearly all system-level demonstrations so far, ranging from optical co妹妹unications, parallel lidar, optical frequency synthesis, low-noise microwave generation to parallel convolutional processing. Yet, transitioning to real-world deployment outside laboratories has been compounded by the difficulty of deterministic soliton microcomb generation, primarily due to strong thermal instabilities. Although a variety of techniques have been developed to initiate soliton generation, including pulsed pumping, fast scanning and auxiliary-laser pumping, these techniques do not eliminate thermal effects and often compromise microcomb performance, either by adding additional complexity or by reducing the accessible soliton existence range. Here we overcome thermal effects and demonstrate deterministic soliton generation in Si3N4photonic integrated circuits. We trace thermal effects to unexpected copper impurities within the waveguides, which originate from residual contaminants in CMOS-grade Si wafers and are gettered into Si3N4during fabrication. By developing copper removal techniques, we substantially reduce copper concentration and thereby mitigate thermal effects. We demonstrate successful dissipative Kerr soliton generation with arbitrary laser scanning profiles and slow laser scanning. Our techniques can be readily applied to front-end-of-line processing of Si3N4devices in foundries, removing a key obstacle to the deployment of soliton microcomb technology.
Optimization by decoded quantum interferometry
解码量子干预干与法实现加速优化
▲作者：Stephen P. Jordan, Noah Shutty, Mary Wootters, Adam Zalcman, Alexander Schmidhuber, Robbie King, et al.
▲ 链接：https://www.nature.com/articles/s41586-025-09527-5
▲ 择要：
实现超多项式加速优化一直是量子算法的焦点目标。
研究组先容相识码量子干预干与法（DQI），这是一种使用量子傅立叶变换将优化问题简化为解码问题的量子算法。当于有限域上迫近最优多项式拟合问题时，DQI与已经知经典算法相比实现了超多项式加速，这源在问题的代数结构被映照于可高效求解的解码问题中。
然后，研究组分析了该要领是否可以加速缺少代数结构但具备稀少子句的优化问题。这些问题被简化为解码低密度的奇偶校验码，已经知其具备强盛的解码器。为了验证这一点，研究组构建了一个最年夜XORSAT实例，DQI比通用的经典开导式算法（如模仿退火）更快找到类似最优解。
只管定制的经典求解器于这类情况下或者优在DQI，但该研究结果注解，将量子傅立叶变换与强盛解码原语相联合，为攻克繁杂优化问题的量子加速提供了一条有远景的新路子。
▲ Abstract：
Achieving superpolynomial speed-ups for optimization has long been a central goal for quantum algorithms. Here we introduce decoded quantum interferometry (DQI), a quantum algorithm that uses the quantum Fourier transform to reduce optimization problems to decoding problems. When approximating optimal polynomial fits over finite fields, DQI achieves a superpolynomial speed-up over known classical algorithms. The speed-up arises because the algebraic structure of the problem is reflected in the decoding problem, which can be solved efficiently. We then investigate whether this approach can achieve a speed-up for optimization problems that lack an algebraic structure but have sparse clauses. These problems reduce to decoding low-density parity-check codes, for which powerful decoders are known. To test this, we construct a max-XORSAT instance for which DQI finds an approximate optimum substantially faster than general-purpose classical heuristics, such as simulated annealing. Although a tailored classical solver can outperform DQI on this instance, our results establish that combining quantum Fourier transforms with powerful decoding primitives provides a promising new path towards quantum speed-ups for hard optimization problems.
Observation of constructive interference at the edge of quantum ergodicity
量子遍历性临界域不雅测到相长干预干与
▲作者：Google Quantum AI and Collaborators
▲ 链接：https://www.nature.com/articles/s41586-025-09526-6
▲ 择要：
量子多系统统的动力学特性由时空疏散点的联系关系函数重构而来的量子不雅测值来表征。然而，于具备快速纠缠孕育发生的动力学中，因为信息加扰的影响，量子不雅测值通常于很长一段时间后对于底层动力学细节掉敏。为了突破该限定，并可以或许获取试验体系中的相干动力学信息，人们已经乐成实现了重复时间反演方案。
研究组试验性地丈量了超导量子处置处罚器上的二阶超时序联系关系函数（OTOC(2)），并发现其于永劫间尺度上对于底层动力学仍连结敏感。此外，OTOC(2)于高度纠缠的量子多系统统中体现出量子联系关系性，若无时间反演技术则没法获取。经由历程于量子演化历程中插入泡利算子，进而相位随机化海森堡图景中泡利字符串的试验方案证实了这一点。
OTOC(2)的丈量值于该方案作用下发生了本色性的变化，从而展现了于构型空间中形成为了年夜环路的泡利字符串之间的相长干预干与。不雅测到的干预干与机制也付与了OTOC(2)高度的经典仿真繁杂性。这些结果，联合OTOC(2)于解析量子动力学有效细节方面的能力（如经由历程哈密顿进修的例子所示），注解了实实际际量子上风的可行路子。
▲ Abstract：快盈VIII官网-
The dynamics of quantum many-body systems is characterized by quantum observables that are reconstructed from correlation functions at separate points in space and time. In dynamics with fast entanglement generation, however, quantum observables generally become insensitive to the details of the underlying dynamics at long times due to the effects of scrambling. To circumvent this limitation and enable access to relevant dynamics in experimental systems, repeated time-reversal protocols have been successfully implemented. Here we experimentally measure the second-order out-of-time-order correlators (OTOC(2)) on a superconducting quantum processor and find that they remain sensitive to the underlying dynamics at long timescales. Furthermore, OTOC(2)manifests quantum correlations in a highly entangled quantum many-body system that are inaccessible without time-reversal techniques. This is demonstrated through an experimental protocol that randomizes the phases of Pauli strings in the Heisenberg picture by inserting Pauli operators during quantum evolution. The measured values of OTOC(2)are substantially changed by the protocol, thereby revealing constructive interference between Pauli strings that form large loops in the configuration space. The observed interference mechanism also endows OTOC(2)with high degrees of classical simulation complexity. These results, combined with the capability of OTOC(2)in unravelling useful details of quantum dynamics, as shown through an example of Hamiltonian learning, indicate a viable path to practical quantum advantage.
Cryogenic X-ray photoelectron spectroscopy for battery interfaces
电池界面的低温X射线光电子能谱
▲作者：Sanzeeda Baig Shuchi, Giulio D’Acunto, Philaphon Sayavong, Solomon T. Oyakhire, Kenzie M. Sanroman Gutierrez, Juliet Risner-Jamtgaard, et al.
▲ 链接：https://www.nature.com/articles/s41586-025-09618-3
▲ 择要：
相识原始界面的化学情况是电化学、质料科学及外貌科学持久寻求的目标。对于锂阳极中的固体电解质界面（SEI）的本色性相识源在X射线光电子能谱（XPS）分析。然而，室温（RT）联合超高真空（UHV）可引诱XPS历程中反映及挥发，造成SEI发生显著蜕变。是以，亟需一种可稳定SEI的表征技术。
研究组开发了具备快速深度冷冻的低温（冷冻）-XPS，并演示了SEI的原位生存。他们发现了UHV中本色上差异的SEI组分及更厚的原始SEI，且没有RT相干的厚度削减及主要组分（包罗LiF及Li2O）的转变。
这类对于原始SEI身分的最新分析实现了差异电解质化学之间的性能联系关系。但最主要的是，研究组夸大了于低温前提下研究敏感界面的须要性。
▲ Abstract：
Understanding the chemical environment of pristine interfaces is a long-sought goal in electrochemistry, materials science and surface science. A substantial understanding of one such interface, the solid electrolyte interphase (SEI) in lithium anodes, originates from X-ray photoelectron spectroscopy (XPS). However, room temperature (RT) combined with ultrahigh vacuum (UHV) can induce major SEI evolution from reactions and volatilization during XPS. Thus, a technique is necessary for SEI stabilization. Here we develop cryogenic (cryo)-XPS with i妹妹ediate plunge freezing and demonstrate SEI preservation. We discover substantially different SEI speciation and a thicker pristine SEI with cryo-XPS, free from RT-associated thickness reduction and alterations to important species, including LiF and Li2O, in UHV. This new access to pristine SEI composition enables performance correlations across diverse electrolyte chemistries. Primarily, we highlight the necessity of studying sensitive interfaces under cryogenic conditions.
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