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. In a paper published today in Nature, 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 Foundations 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 LIGOs 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, a research scientist at MITs Kavli Institute for Astrophysics and Space Research.
The researchers used a special instrument that they designed, called a quantum squeezer, to manipulate the detectors quantum noise and reduce its kicks to the mirrors, in a way that could ultimately improve LIGOs sensitivity in detecting gravitational waves, explains Haocun Yu, a physics graduate student at MIT.
Whats special about this experiment is weve seen quantum effects on something as large as a human, says Nergis Mavalvala, the Marble Professor and associate head of the physics department at MIT. We too, every nanosecond of our existence, are being kicked around, buffeted by these quantum fluctuations. Its just that the jitter of our existence, our thermal energy, is too large for these quantum vacuum fluctuations to affect our motion measurably. With LIGOs mirrors, weve done all this work to isolate them from thermally driven motion and other forces, so that they are now still enough to be kicked around by quantum fluctuations and this spooky popcorn of the universe.
Yu, Mavalvala, and McCuller are co-authors of the new paper, along with graduate student Maggie Tse and Principal Research Scientist Lisa Barsotti at MIT, along with other members of the LIGO Scientific Collaboration.
A quantum kick
LIGO is designed to detect gravitational waves arriving at the Earth from cataclysmic sources millions to billions of light years away. It comprises twin detectors, one in Hanford, Washington, and the other in Livingston, Louisiana. Each detector is an L-shaped interferometer made up of two 4-kilometer-long tunnels, at the end of which hangs a 40-kilogram mirror.
To detect a gravitational wave, a laser located at the input of the LIGO interferometer sends a beam of light down each tunnel of the detector, where it reflects off the mirror at the far end, to arrive back at its starting point. In the absence of a gravitational wave, the lasers should return at the same exact time. If a gravitational wave passes through, it would briefly disturb the position of the mirrors, and therefore the arrival times of the lasers.
Much has been done to shield the interferometers from external noise, so that the detectors have a better chance of picking out the exceedingly subtle disturbances created by an incoming gravitational wave.
Mavalvala and her colleagues wondered whether LIGO might also be sensitive enough that the instrument might even feel subtler effects, such as quantum fluctuations within the interferometer itself, and specifically, quantum noise generated among the photons in LIGOs laser.
This quantum fluctuation in the laser light can cause a radiation pressure that can actually kick an object, McCuller adds. The object in our case is a 40-kilogram mirror, which is a billion times heavier than the nanoscale objects that other groups have measured this quantum effect in.
To see whether they could measure the motion of LIGOs massive mirrors in response to tiny quantum fluctuations, the team used an instrument they recently built as an add-on to the interferometers, which they call a quantum squeezer. With the squeezer, scientists can tune the properties of the quantum noise within LIGOs interferometer.
The team first measured the total noise within LIGOs interferometers, including the background quantum noise, as well as classical noise, or disturbances generated from normal, everyday vibrations. They then turned the squeezer on and set it to a specific state that altered the properties of quantum noise specifically. They were able to then subtract the classical noise during data analysis, to isolate the purely quantum noise in the interferometer. As the detector constantly monitors the displacement of the mirrors to any incoming noise, the researchers were able to observe that the quantum noise alone was enough to displace the mirrors, by 10-20 meter.
Mavalvala notes that the measurement lines up exactly with what quantum mechanics predicts. But still its remarkable to see it be confirmed in something so big, she says.
Going a step further, the team wondered whether they could manipulate the quantum squeezer to reduce the quantum noise within the interferometer. The squeezer is designed such that when it set to a particular state, it squeezes certain properties of the quantum noise, in this case, phase and amplitude. Phase fluctuations can be thought of as arising from the quantum uncertainty in the light's travel time, while amplitude fluctuations impart quantum kicks to the mirror surface.
We think of the quantum noise as distributed along different axes, and we try to reduce the noise in some specific aspect, Yu says.
When the squeezer is set to a certain state, it can for example squeeze, or narrow the uncertainty in phase, while simultaneously distending, or increasing the uncertainty in amplitude. Squeezing the quantum noise at different angles would produce different ratios of phase and amplitude noise within LIGOs detectors.
The group wondered whether changing the angle of this squeezing would create quantum correlations between LIGOs lasers and its mirrors, in a way that they could also measure. Testing their idea, the team set the squeezer to 12 different angles and found that, indeed, they could measure correlations between the various distributions of quantum noise in the laser and the motion of the mirrors.
Through these quantum correlations, the team was able to squeeze the quantum noise, and the resulting mirror displacement, down to 70 percent its normal level. This measurement, incidentally, is below whats called the standard quantum limit, which, in quantum mechanics, states that a given number of photons, or, in LIGOs case, a certain level of laser power, is expected to generate a certain minimum of quantum fluctuations that would generate a specific kick to any object in their path.
By using squeezed light to reduce the quantum noise in the LIGO measurement, the team has made a measurement more precise than the standard quantum limit, reducing that noise in a way that will ultimately help LIGO to detect fainter, more distant sources of gravitational waves.
This research was funded, in part, by the National Science Foundation.
- New quantum particle may have been accidentally discovered - New Atlas - January 13th, 2021
- Exploring the unanswered questions of our universe with quantum technologies - University of Birmingham - January 13th, 2021
- Wormholes may be lurking in the universe and new studies are proposing ways of finding them - The Conversation UK - January 13th, 2021
- Surprising Discovery of Unexpected Quantum Behavior in Insulators Suggests Existence of Entirely New Type of Particle - SciTechDaily - January 13th, 2021
- New quantum technology projects to solve mysteries of the universe - Open Access Government - January 13th, 2021
- University of Sheffield to lead multi-million pound project which could open up a new frontier in physics - University of Sheffield News - January 13th, 2021
- The Greatest: Four Legends Gather in One Night in Miami - Memphis Flyer - January 13th, 2021
- Raytheon UK part of team transforming the Royal Navy's technology, training and learning solutions - PRNewswire - January 13th, 2021
- Optical selection and sorting of nanoparticles according to quantum mechanical properties - Science Advances - January 13th, 2021
- Birds Have a Mysterious 'Quantum Sense'. For The First Time, Scientists Saw It in Action - ScienceAlert - January 9th, 2021
- The unhackable computers that could revolutionize the future - CNN - January 9th, 2021
- How understanding light has led to a hundred years of bright ideas - The Economist - January 9th, 2021
- Quantum Nanodevice Can Be Both a Heat Engine and Refrigerator at the Same Time - SciTechDaily - January 9th, 2021
- Illumination at the limits of knowledge - The Economist - January 9th, 2021
- Detective Work in Theoretical Physics: Comprehensive Review of Physics of Interacting Particles - SciTechDaily - January 5th, 2021
- The 10 biggest physics stories of 2020 - Livescience.com - January 5th, 2021
- The Schrodinger Equation appears in Criminal Minds - Looper - January 5th, 2021
- Op-Ed: The universe is just a thought, says new theory Or maybe not - Digital Journal - December 26th, 2020
- Here's Why Quantum Computing Will Not Break Cryptocurrencies - Forbes - December 26th, 2020
- Quantum Superposition Evidenced by Measuring Interaction of Light with Vibration - AZoQuantum - December 26th, 2020
- A state of vibration that exists simultaneously at two different times - Tech Explorist - December 26th, 2020
- The Secret Science of Santa - ZME Science - December 26th, 2020
- Matter Deconstructed: The Observer Effect and Photography - PetaPixel - December 26th, 2020
- MIT's quantum entangled atomic clock could still be ticking after billions of years - SYFY WIRE - December 26th, 2020
- If the multiverse exists, are there infinite copies of me? - New Scientist - December 12th, 2020
- What We Are Reading Today: Understanding Quantum Mechanics by Roland Omnes - Arab News - December 12th, 2020
- The Upcoming Women In Quantum Summit III And Its Secret 70 Year-Old Legacy - Forbes - December 12th, 2020
- International Relations goes quantum - News - The University of Sydney - December 12th, 2020
- Scientists just engineered the perfect friction-less fluid and here's what it sounds like! - SYFY WIRE - December 12th, 2020
- MIT Physicists Created a Perfect Fluid and Captured the Sound Listen Here - SciTechDaily - December 12th, 2020
- How Could Quantum Sensing Transform Industries and our Society? - AZoSensors - December 12th, 2020
- The Unbroken Story Birth of the Universe to the Big Bang & Beyond - The Daily Galaxy --Great Discoveries Channel - December 12th, 2020
- Combining Quantum Physics and the Theory of Relativity: Sound-Waves From a Quantum Vacuum at the Black Hole Laboratory - SciTechDaily - November 29th, 2020
- Direct Visualization of Quantum Dots Reveals Shape of Quantum Wave Function of the Trapped Electrons - SciTechDaily - November 29th, 2020
- Quantum Mechanics and the Upholding Power of God - National Catholic Register - November 29th, 2020
- Physicists introduced the notion of the quantum magic square - Tech Explorist - November 29th, 2020
- This physicist keeps the science in Marvel's movies accurate (ish) - Wired.co.uk - November 29th, 2020
- Quantum Time Twist Offers a Way to Create Schrdinger's Clock - Scientific American - October 25th, 2020
- Quantum Tunnels Show How Particles Can Break the Speed of Light - Quanta Magazine - October 25th, 2020
- The Importance of Funding Quantum Physics, Even in a Pandemic - Inside Philanthropy - October 25th, 2020
- Quantum Physics and Early Death | Dan Peterson - Patheos - October 25th, 2020
- A New Timekeeping Theory Reconciles Einstein's Relativity and Quantum Clocks - Science Times - October 25th, 2020
- Archer Materials well-aligned with strategic direction of the US in quantum computing - Proactive Investors Australia - October 25th, 2020
- Could Schrdingers cat exist in real life? We propose an experiment to find out - Scroll.in - October 25th, 2020
- Every Thing You Need to Know About Quantum Computers - Analytics Insight - October 25th, 2020
- Physicists clock the fastest possible speed of sound - Live Science - October 25th, 2020
- Post-doctoral Fellow, Department of Physics job with THE UNIVERSITY OF HONG KONG | 230760 - Times Higher Education (THE) - October 25th, 2020
- Diamonds Are a Quantum Scientist's Best Friend: Discovery May Revolutionize the High-Tech Industry - SciTechDaily - October 25th, 2020
- Sumit Das to Deliver 2019-20 A&S Distinguished Professor Lecture on 'Deconstructing Space-Time' - UKNow - October 25th, 2020
- Column: A new era of electric vehicles could be on the way - Gainesville Times - October 25th, 2020
- The TRP turf - The Times of India Blog - October 25th, 2020
- Beyond Homo Sapiens A Slightly Different Roll of the Darwinian Dice (Weekend Feature) - The Daily Galaxy --Great Discoveries Channel - October 25th, 2020
- Quantum and classical computers handle time differently. What does that mean for AI? - The Next Web - September 18th, 2020
- The Fate of Schrdinger's Cat Probably Isn't in The Hands of Gravity, Experiment Finds - ScienceAlert - September 18th, 2020
- Hybrid lightmatter particles offer tantalising new way to control chemistry - Chemistry World - September 18th, 2020
- Scientists Have Shown There's No 'Butterfly Effect' in the Quantum World - VICE - August 19th, 2020
- How Physics Erases The Beginning Of The Universe - Forbes - August 19th, 2020
- Does the Butterfly Effect Exist? Maybe, But Not in the Quantum Realm - Discover Magazine - August 19th, 2020
- Dismantling disciplinary boundaries and decolonizing young India: Decoding the National Educational Policy (20 - The Times of India Blog - August 19th, 2020
- The spread of 'stranger than we can think' - Yahoo Lifestyle - August 19th, 2020
- Raytheon Technologies invests in new transformational STEM high school - PRNewswire - August 19th, 2020
- The Wheel of Time and the Storytelling Problem in the Concept of a Binary - tor.com - August 19th, 2020
- Physicists witness time crystals interacting for the first time ever - New Atlas - August 19th, 2020
- Quantum mechanics is immune to the butterfly effect - The Economist - August 17th, 2020
- Major quantum computational breakthrough is shaking up physics and maths - The Conversation UK - August 17th, 2020
- Physicists watch quantum particles tunnel through solid barriers. Here's what they found. - Space.com - August 17th, 2020
- The science of marketing: taking inspiration from quantum physics - The Drum - August 17th, 2020
- Here's why we need to build a quantum security coalition - World Economic Forum - August 17th, 2020
- The Spread of 'Stranger Than We Can Think' - SFGate - August 17th, 2020
- Nuh Gedik and Pablo Jarillo-Herrero are 2020 Moore Experimental Investigators in Quantum Materials - MIT News - August 17th, 2020
- Students in the news | Announcements - Indiana Gazette - August 17th, 2020
- Indian American Engineer Develops Parachute That Helped Curiosity Land on Mars - India West - August 17th, 2020
- How Quantum Mechanics will Change the Tech Industry - Unite.AI - July 21st, 2020
- Money & Markets: After the virus, make sure you've read the inflationary playbook - E&T Magazine - July 21st, 2020
- Bruce Lee: Inside the mind of the martial arts icon - CNN - July 21st, 2020
- Read Before Pontificating on Quantum Technology - War on the Rocks - July 13th, 2020
- The universe's clock might have bigger ticks than we imagine - Livescience.com - July 13th, 2020
- Testing Einstein's theory of relativity | OUPblog - OUPblog - July 13th, 2020
- Scientists Say This Is the Smallest Unit of Time That Could Exist - lintelligencer - July 13th, 2020
- Study: The Period of the Universe's Clock - lintelligencer - July 13th, 2020