《自然》（20230928出版）一周论文导读

 
 
《自然》（20230928出版）一周论文导读  
 

 

编译 | 未玖

Nature, 28 September 2023, VOL 621, ISSUE 7980

《自然》2023年9月28日，第621卷，7980期

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天文学Astronomy

Precessing jet nozzle connecting to a spinning black hole in M87

进动喷流连接M87旋转黑洞

▲ 作者：Yuzhu Cui, Kazuhiro Hada, Tomohisa Kawashima, Motoki Kino, Weikang Lin, Yosuke Mizuno, et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06479-6

▲ 摘要：

邻近射电星系M87为探索中央超大质量黑洞和相对论喷流之间的相关性提供了一个独特机会。先前对M87内部区域的研究显示，起源于黑洞附近的喷流有一个大开口角。

事件视界望远镜对中央射电源进行了解析，发现了一个与广义相对论预测相符的不对称环状结构。根据17年的观测基线，喷流横向位置发生了变化，这可能由8到10年的准周期性引发。然而，这种横向转变的起源仍不清楚。

研究组报道了对22年来射电观测的分析，表明喷流位置角度的变化周期约为11年，因而推断观测到的是一个旋转的黑洞，它引起了一个错位吸积盘的兰斯-蒂林进动。类似的喷流进动通常也发生在其他活动星系核中，但由于其变化幅度小且周期长，因此很难探测到。

▲ Abstract：

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from general relativity. With a baseline of 17 years of observations, there was a shift in the jet’s transverse position, possibly arising from an 8- to 10-year quasi-periodicity. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years for the variation in the position angle of the jet. We infer that we are seeing a spinning black hole that induces the Lense–Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.

物理学Physics

A quantum engine in the BEC–BCS crossover

BEC-BCS交叉中的量子引擎

▲ 作者：Jennifer Koch, Keerthy Menon, Eloisa Cuestas, Sian Barbosa, Eric Lutz, Thomás Fogarty, et al.

▲ 链接：

https://www.nature.com/articles/s41586-023-06469-8

▲ 摘要：

热机将热能转化为经典和量子状态下的机械功。然而，量子理论提供了真正的非经典形式的能量，不同于迄今为止尚未在循环发动机中得到利用的热能。

研究组通过实验实现了一个由费米子和玻色子超冷粒子系综之间的能量差驱动的量子多体引擎，且遵循泡利不相容原理。

使用一种由近磁性费什巴赫共振6Li原子组成的谐波捕获超流体气体，通过磁场调节玻色子分子的玻色-爱因斯坦凝聚体和酉费米气体（以及返回）之间的气体，有效改变了从玻色-爱因斯坦到费米-狄拉克的量子统计。

通过将泡利引擎与经典热机和纯相互作用驱动的设备进行对比，泡利引擎的量子性质得以揭示。研究组获得了每周期几个106振动量子的功输出，效率高达25%。该发现将量子统计学确立为可做功的有用热力学资源。

▲ Abstract：

Heat engines convert thermal energy into mechanical work both in the classical and quantum regimes. However, quantum theory offers genuine non-classical forms of energy, different from heat, which so far have not been exploited in cyclic engines. Here we experimentally realize a quantum many-body engine fuelled by the energy difference between fermionic and bosonic ensembles of ultracold particles that follows from the Pauli exclusion principle. We employ a harmonically trapped superfluid gas of 6Li atoms close to a magnetic Feshbach resonance that allows us to effectively change the quantum statistics from Bose–Einstein to Fermi–Dirac, by tuning the gas between a Bose–Einstein condensate of bosonic molecules and a unitary Fermi gas (and back) through a magnetic field. The quantum nature of such a Pauli engine is revealed by contrasting it with an engine in the classical thermal regime and with a purely interaction-driven device. We obtain a work output of several 106 vibrational quanta per cycle with an efficiency of up to 25%. Our findings establish quantum statistics as a useful thermodynamic resource for work production.

材料科学Materials Science

Electrically driven organic laser using integrated OLED pumping

采用集成OLED泵浦的电驱动有机激光器

▲ 作者：Kou Yoshida, Junyi Gong, Alexander L. Kanibolotsky, Peter J. Skabara, Graham A. Turnbull & Ifor D. W. Samuel

▲ 链接：

https://www.nature.com/articles/s41586-023-06488-5

▲ 摘要：