新技术令我们可以观察到布朗运动
服装经营技巧
爱因斯坦当年认为当时不可能实现的事情现在能实现了2013年研究生国家线，科学家能利用超高速位置探测器和光阱捕捉到布朗运动的粒子图像。报告发表在《Nature Physics》上。
成都军训公元前60年，诗人卢克莱修描绘了暗室里的灰尘运动，推测了原子的存在。1827年，英国植物学罗伯特·布朗利用显微镜观察悬浮于水中的花粉，发现了用他名字命名的布朗运动。1905年，爱因斯坦完整揭示了布朗运动的原因——onestepatatime花粉粒子在水分子撞击下受力不均导致的瞬间失衡。爱因斯坦计算得出，粒子减速的时间极短，几乎难以察觉，当时的技术不可能测量。现在，研究人员的探测设备（分辨率什么是紧急制动>鞍山辅导拆除英语0.2埃，瞬时分辨率10ns）已经足够快到能跟踪运动的粒子。
2D random walk
Christopher Dombrowski
六级成绩什么时候公布2021年6月New tech shows Einstein wrong: we can watch Brownian motion
By Christopher Dombrowski
The emingly random movement of Brownian motion just got a little more classical. Scientists have been able to image the ultrafast motions of a trapped particle, revealing the underlining trajectories causing Brownian motion. This is the first time inertial Brownian motion of a particle in a fluid have been measured.
In 60 BC, the poet Lucretius described the motions of dust in a dark room and speculated on the existence of atoms. In 1827, Robert Brown described the random motions of pollen in water, the motion which now bears his name. It took until 1905 for Einstein to fully describe how Brownian motion aris from instantaneous imbalances in the forces from collisions with water molecules.
At its heart, Brownian motion is still described by classical Newtonian physics, even if we cannot define a classical velocity and can only measure mean square displacement. Einstein said, "It is to ascertain the root mean square velocity by obrvation" becau the timescales of the instantaneous velocity are vanishingly short. Einstein calculated that the time for a particle to decelerate significantly is about ~100ns, impossibly fast to measure at the time.
But that was then. Now rearchers have been able to probe time scales an order of magnitude faster. By holding a micron-sized sphere in a optical trap and measuring the scattered light with a high speed position detector (75MHz), a team was able to measure the motion of the spheres with a resolution of 0.2 angstroms and a temporal resolution of ~10ns. At the resolutions, they were able to track the inertial Brownian motion of the sphere.
interpretative dance
Nature Physics, 2011. DOI: 10.1038/NPHYS1953 (About DOIs).
