$10^{-18}$ -- 人类有史以来最精确的时钟(The most accurate clock we ever built)

$10^{-18}$ -- 人类有史以来最精确的时钟(The most accurate clock we ever built)

时间一直以来都是一个很有意思的概念,先贤们也对此争论不休。当然,时间也在方方面面影响着人们的生活。自古就有“日出而作,日落而息”的说法。虽然来到近代,我们已经(很大程度上)脱离了日晷,摆钟,石英钟和电子表,逐渐习惯了智能手机和智能手表。我们仅需要连接网络,智能设备就可以自动设定当前的时间。而这背后,少不了一个叫做“原子钟”(Atomic clock)的设备。

原子钟可以以惊人的精度来测量时间。以1999年的数据为例,原子钟在600万年内的误差还不到一秒。而最近,一项新技术使得原子钟的精度更上一层楼。

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Job hunting resources for Ph.D. students in CMP/AMO physics and related fields

Note added 5/28/2020: I just learnt that there’s a tool called UIUC Fellowship Finder. While completing excellent research work is the most important thing for a Ph.D. student, selling yourself is also critical to your career. Getting a fellowship from big tech companies like Google, IBM and Microsoft in the early stage of your Ph.D. study would definitely boost your future career significantly. It’s really a pit that I only get to know this when I’m about to graduating.

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Grover Search as a Naturally Occurring Phenomenon

A few days ago, when I was browsing papers recently accepted by Phys. Rev. Lett. I noticed an interesting article Grover Search as a Naturally Occurring Phenomenon, which has just been published online today. I found this work really very fascinating, so I write this short note describing the work.

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AlphaZero explores global optimization of quantum dynamics in superconducting circuit QED

AlphaZero explores global optimization of quantum dynamics in superconducting circuit QED

I’ve been thinking about a class of optimization problems on a quantum computer and wish to explore them with machine learning algorithms, especially reinforcement learning, as it does not require a good initial guess (radom, intuition or whatever). More recently, I came across to the paper “Global optimization of quantum dynamics with AlphaZero deep exploration”, which has been published online about 2 weeks ago. While the authors considered a rather ideal situation, their work did shed lights on my research. So, I prepare this note to briefly discuss their work and some relevant topics.

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Renormalization group analysis of stability of band crossing in spin-1 spin-orbit coupled degenerate Fermi gas

In one of my recent paper entitled Topological phases in spin-1 Fermi gases with two-dimensional spin-orbit coupling, we study the topological phases of Rashba spin-orbit (SO) coupled three-component Fermi gases. In fact, I also investigated the stability of the band crossings under repulsive $SU(3)$-invariant interactions, which is not included in the paper. In the following, I share my note on this matter.

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Beyond mean field theory: the renormalization group idea