Month: July 2020

Enlarge / The mirrors of LIGO are a bit large to be experiencing quantum effects. (credit: Caltech/MIT/LIGO Lab)

Quantum effects are generally thought of as small and fragile. Typically, we're only able to detect them when things are tiny and kept near absolute zero, and they're swamped by non-quantum effects outside of those conditions. Mostly. In Wednesday's issue of Nature, researchers are reporting that quantum effects can be detected in some very large objects: the 40kg mirrors of the Laser Interferometer Gravitational-Wave Observatory, or LIGO.

The paper details how researchers were able to detect noise in the mirrors of LIGO caused by quantum fluctuations in the light reflecting off them. And by adding some specially prepared light, the researchers limited that noise, allowing increased sensitivity in the detection of gravitational waves.

Putting on the squeeze

There are plenty of sources of noise in the LIGO hardware. Key hardware sits inside a vacuum chamber, but we can't really eliminate all stray molecules from bumping into it. The mirrors are kept at room temperature, so there's some thermal noise that's always interfering with our measurements. And then there's quantum noise. LIGO is based on mirrors separated by kilometers reflecting laser beams back and forth multiple times. And those laser beams are composed of photons that obey the rules of quantum mechanics.

Enlarge / A Tesla facility in Lathrop, CA. (credit: Andrei Stanescu / Getty)

Tesla has surprised Wall Street again with better-than-expected delivery numbers. The electric carmaker delivered 90,650 vehicles in the second quarter of 2020, up slightly from the 88,400 vehicles delivered in the first quarter. This despite the fact that Tesla's main factory in Fremont, California, was shut down by county officials for the first half of the quarter.

Tesla's stock leapt at the news. After closing at a record high of $1,120 yesterday, Tesla's shares rose above $1,200 in pre-market trading on Thursday morning.

While Tesla's Q2 deliveries were up from the previous quarter, they're down slightly from the 95,200 vehicles produced in the second quarter of 2019. Tesla also delivered more cars in Q3 and Q4 of 2019 than it did last quarter. That presumably reflects the effects of the coronavirus over the last two quarters, as well as the phaseout of the federal tax credit for purchasing a Tesla. The credit fell by half on June 30, 2019 and phased out completely on December 31.