MIT: Quantum Fluctuations Can Jiggle Human-Scale Objects

[bystander]

Quantum Fluctuations Can Jiggle Objects on the Human-Scale
Massachusetts Institute of Technology | 2020 Jul 01

Study shows LIGO’s 40-kilogram mirrors can move in response to tiny quantum effects, revealing the “spooky popcorn of the universe.”

MIT physicists have observed that LIGO’s 40-kilogram mirrors can move in response to tiny quantum effects. In this photo, a LIGO optics technician inspects one of LIGO’s mirrors. Credit: Matt Heintze/Caltech/MIT/LIGO Lab

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The universe, as seen through the lens of quantum mechanics, is a noisy, crackling space where particles blink constantly in and out of existence, creating a background of quantum noise whose effects are normally far too subtle to detect in everyday objects.

Now for the first time, a team led by researchers at MIT LIGO Laboratory has measured the effects of quantum fluctuations on objects at the human scale. ... the researchers report observing that quantum fluctuations, tiny as they may be, can nonetheless “kick” an object as large as the 40-kilogram mirrors of the U.S. National Science Foundation’s Laser Interferometer Gravitational-wave Observatory (LIGO), causing them to move by a tiny degree, which the team was able to measure.

It turns out the quantum noise in LIGO’s detectors is enough to move the large mirrors by 10-20 meters — a displacement that was predicted by quantum mechanics for an object of this size, but that had never before been measured.

“A hydrogen atom is 10-10 meters, so this displacement of the mirrors is to a hydrogen atom what a hydrogen atom is to us — and we measured that,” says Lee McCuller ...

The researchers used a special instrument that they designed, called a quantum squeezer, to “manipulate the detector’s quantum noise and reduce its kicks to the mirrors, in a way that could ultimately improve LIGO’s sensitivity in detecting gravitational waves,” explains Haocun Yu ...

Quantum fluctuations have been shown to affect macroscopic objects
Nature News and Views | 2020 Jul 01

Quantum correlations between light and the kilogram-mass mirrors of LIGO ~ Haocun Yu et al

• Nature 583(7814):43 (02 July 2020) DOI: 10.1038/s41586-020-2420-8
• arXiv.org > quant-ph > arXiv:2002.01519 > 04 Feb 2020

viewtopic.php?t=40078

[bystander]

Portable System Boosts Laser Precision, at Room Temperature
Massachusetts Institute of Technology | 2020 Jul 07

“Light squeezer” reduces quantum noise in lasers, could enhance quantum computing and gravitational-wave detection.

An MIT-designed miniature “squeezer” reduces quantum noise in lasers at room temperature. The marble-sized system could enable better laser precision for quantum computing and gravitational-wave detection. This illustration shows an artist’s interpretation of the system. Credit: Christine Daniloff, MIT

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Physicists at MIT have designed a quantum “light squeezer” that reduces quantum noise in an incoming laser beam by 15 percent. It is the first system of its kind to work at room temperature, making it amenable to a compact, portable setup that may be added to high-precision experiments to improve laser measurements where quantum noise is a limiting factor.

The heart of the new squeezer is a marble-sized optical cavity, housed in a vacuum chamber and containing two mirrors, one of which is smaller than the diameter of a human hair. The larger mirror stands stationary while the other is movable, suspended by a spring-like cantilever.

The shape and makeup of this second “nanomechanical” mirror is the key to the system’s ability to work at room temperature. When a laser beam enters the cavity, it bounces between the two mirrors. The force imparted by the light makes the nanomechanical mirror swing back and forth in a way that allows the researchers to engineer the light exiting the cavity to have special quantum properties.

The laser light can exit the system in a squeezed state, which can be used to make more precise measurements, for instance, in quantum computation and cryptology, and in the detection of gravitational waves. ...

Squeezing Hots Up
Nature Physics | News & Views | 2020 Jul 07

Room-Temperature Optomechanical Squeezing ~ Nancy Aggarwal et al

• Nature Physics 16(7):774 (July 2020) DOI: 10.1038/s41567-020-0877-x
• arXiv.org > quant-ph > arXiv:1812.09942 > 24 Dec 2018