Quantum entanglement remains one of the most challenging fields of study for modern physicists. Described by Einstein as spooky action at a distance, scientists have long sought to reconcile how this aspect of quantum mechanics can coexist with classical mechanics. Essentially, the fact that two particles can be connected over great distances violates the rules of locality and realism.
Formally, this is a violation of Bells Ineqaulity, a theory which has been used for decades to show that locality and realism are valid despite being inconsistent with quantum mechanics. However, in a recent study, a team of researchers from the Ludwig-Maximilian University (LMU) and the Max Planck Institute for Quantum Optics in Munich conducted tests which once again violate Bells Inequality and proves the existence of entanglement.
Their study, titled Event-Ready Bell Test Using Entangled Atoms Simultaneously Closing Detection and Locality Loopholes, was recently published in the Physical Review Letters. Led by Wenjamin Rosenfeld, a physicist at LMU and the Max Planck Institute for Quantum Optics, the team sought to test Bells Inequality by entangling two particles at a distance.
John Bell, the Irish physicist who devised a test to show that nature does not hide variables as Einstein had proposed. Credit: CERN
Bells Inequality (named after Irish physicist John Bell, who proposed it in 1964) essentially states that properties of objects exist independent of being observed (realism), and no information or physical influence can propagate faster than the speed of light (locality). These rules perfectly described the reality we human beings experience on a daily basis, where things are rooted in a particular space and time and exist independent of an observer.
However, at the quantum level, things do not appear to follow these rules. Not only can particles be connected in non-local ways over large distances (i.e. entanglement), but the properties of these particles cannot be defined until they are measured. And while all experiments have confirmed that the predictions of quantum mechanics are correct, some scientists have continued to argue that there are loopholes that allow for local realism.
To address this, the Munich team conducted an experiment using two laboratories at LMU. While the first lab was located in the basement of the physics department, the second was located in the basement of the economics department roughly 400 meters away. In both labs, teams captured a single rubidium atom in an topical trap and then began exciting them until they released a single photon.
As Dr. Wenjamin Rosenfeld explained in an Max Planck Institute press release:
Our two observer stations are independently operated and are equipped with their own laser and control systems. Because of the 400 meters distance between the laboratories, communication from one to the other would take 1328 nanoseconds, which is much more than the duration of the measurement process. So, no information on the measurement in one lab can be used in the other lab. Thats how we close the locality loophole.
The experiment was performed in two locations 398 meters apart at the Ludwig Maximilian University campus in Munich, Germany. Credit: Rosenfeld et al/American Physical Society
Once the two rubidium atoms were excited to the point of releasing a photon, the spin-states of the rubidium atoms and the polarization states of the photons were effectively entangled. The photons were then coupled into optical fibers and guided to a set-up where they were brought to interference. After conducting a measurement run for eight days, the scientists were able to collected around 10,000 events to check for signs entanglement.
This would have been indicated by the spins of the two trapped rubidium atoms, which would be pointing in the same direction (or in the opposite direction, depending on the kind of entanglement). What the Munich team found was that for the vast majority of the events, the atoms were in the same state (or in the opposite state), and that there were only six deviations consistent with Bells Inequality.
These results were also statistically more significant than those obtained by a team of Dutch physicists in 2015. For the sake of that study, the Dutch team conducted experiments using electrons in diamonds at labs that were 1.3 km apart. In the end, their results (and other recent tests of Bells Inequality) demonstrated that quantum entanglement is real, effectively closing the local realism loophole.
As Wenjamin Rosenfeld explained, the tests conducted by his team also went beyond these other experiments by addressing another major issue. We were able to determine the spin-state of the atoms very fast and very efficiently, he said. Thereby we closed a second potential loophole: the assumption, that the observed violation is caused by an incomplete sample of detected atom pairs.
By obtaining proof of the violation of Bells Inequality, scientists are not only helping to resolve an enduring incongruity between classical and quantum physics. They are also opening the door to some exciting possibilities. For instance, for years, scientist have anticipated the development of quantum processors, which rely on entanglements to simulate the zeros and ones of binary code.
Computers that rely on quantum mechanics would be exponentially faster than conventional microprocessors, and would ushering in a new age of research and development. The same principles have been proposed for cybersecurity, where quantum encryption would be used to cypher information, making it invulnerable to hackers who rely on conventional computers.
Last, but certainly not least, there is the concept of Quantum Entanglement Communications, a method that would allow us to transmit information faster than the speed of light. Imagine the possibilities for space travel and exploration if we are no longer bound by the limits of relativistic communication!
Einstein wasnt wrong when he characterized quantum entanglements as spooky action. Indeed, much of the implications of this phenomena are still as frightening as they are fascinating to physicists. But the closer we come to understanding it, the closer we will be towards developing an understanding of how all the known physical forces of the Universe fit together aka. a Theory of Everything!
Further Reading: LMU, Physical Review Letters
By Matt Williams- Matt Williams is the Curator of Universe Today’s Guide to Space. He is also a freelance writer, a science fiction author and a Taekwon-Do instructor. He lives with his family on Vancouver Island in beautiful British Columbia.
Bell’s Inequality, classical physics, Featured, Max Planck Institute for Quantum Optics, quantum entanglement, quantum mechanics
- China bet big on quantum computing. Now the US races to ... - October 26th, 2018
- US takes first step toward a quantum computing workforce ... - September 17th, 2018
- China bet big on quantum computing. Now the ... - money.cnn.com - September 17th, 2018
- The reality of quantum computing could be just three years ... - September 12th, 2018
- The quantum computing race the US cant afford to lose - September 3rd, 2018
- Quantum Computing | USRA - August 30th, 2018
- What Is Quantum Computing? The Complete WIRED Guide | WIRED - August 22nd, 2018
- Quantum Computing Market Research Report- Forecast 2022 | MRFR - August 1st, 2018
- Two Quantum Computing Bills Are Coming To Congress - July 5th, 2018
- Senate bills would make quantum computing a priority - June 10th, 2018
- What is quantum computing? - Definition from WhatIs.com - February 5th, 2018
- The Era of Quantum Computing Is Here. Outlook: Cloudy ... - January 26th, 2018
- IBM puts its quantum computer to work in relaxing, nerdy ASMR ... - January 8th, 2018
- Quantum computing is going to change the world. Here's what ... - January 8th, 2018
- Is Quantum Computing an Existential Threat to Blockchain ... - December 25th, 2017
- What is Quantum Computing? | SAP News Center - December 23rd, 2017
- Quantum Computing Explained | What is Quantum Computing? - December 21st, 2017
- New silicon structure opens the gate to quantum computers - December 14th, 2017
- Microsoft offers developers a preview of its quantum ... - December 12th, 2017
- Quantum Computing Is the Next Big Security Risk | WIRED - December 8th, 2017
- Yale Professors Race Google and IBM to the First Quantum ... - November 16th, 2017
- IBM's processor pushes quantum computing ... - engadget.com - November 16th, 2017
- Quantum computing - news.microsoft.com - November 1st, 2017
- Intel Takes First Steps To Universal Quantum Computing - October 13th, 2017
- Qudits: The Real Future of Quantum Computing? - IEEE Spectrum - October 13th, 2017
- quantum computing - engadget.com - October 13th, 2017
- Quantum Computing | Intel Newsroom - October 13th, 2017
- What will you actually use quantum computing for? | ZDNet - October 11th, 2017
- Here's what quantum computing is and why it matters - October 6th, 2017
- Microsoft just upped its multi-million bet on quantum computing - ZDNet - September 7th, 2017
- Microsoft's Aussie quantum computing lab set to scale up next-gen ... - ARNnet - September 7th, 2017
- An Entirely New Type of Quantum Computing Has Just Been Invented - Futurism - September 7th, 2017
- Quantum computing event explores the implications for business - Cambridge Network - August 30th, 2017
- Quantum Computing Is Coming at Us Fast, So Here's Everything You Need to Know - ScienceAlert - August 27th, 2017
- How quantum mechanics can change computing - San Francisco ... - San Francisco Chronicle - August 25th, 2017
- Commonwealth Bank investing in Australia's first quantum computer company - Which-50 (blog) - August 25th, 2017
- How quantum mechanics can change computing - The Conversation US - August 23rd, 2017
- Introducing Australia's first quantum computing hardware company - Computerworld Australia - August 23rd, 2017
- IEEE Approves Standards Project for Quantum Computing ... - insideHPC - August 23rd, 2017
- $495.3 Million Quantum Computing Market 2017 by Revenue Source, Application, Industry, and Geography - Global ... - PR Newswire (press release) - August 18th, 2017
- Physicists Have Made Exotic Quantum States From Light - Futurism - August 16th, 2017
- Machine learning tackles quantum error correction - Phys.Org - August 15th, 2017
- Quantum Internet Is 13 Years Away. Wait, What's Quantum Internet? - WIRED - August 15th, 2017
- Blind quantum computing for everyone - Phys.org - Phys.Org - August 12th, 2017
- Quantum Computing Is Real, and D-Wave Just Open ... - WIRED - August 12th, 2017
- Quantum Computing Market Worth 495.3 Million USD by 2023 | 08 ... - Markets Insider - August 10th, 2017
- China uses a quantum satellite to transmit potentially unhackable data - CNBC - August 10th, 2017
- Why you might trust a quantum computer with secretseven over ... - Phys.Org - July 12th, 2017
- Quantum-computer node uses two different ion species - physicsworld.com - July 10th, 2017
- Quantum Computers vs Bitcoin How Worried Should We Be? - The Merkle - July 10th, 2017
- Quantum cheques could be a forgery-free way to move money - New Scientist - July 10th, 2017
- Technique for measuring and controlling electron state is a ... - UCLA Newsroom - July 9th, 2017
- Quantum Computers Made Even More Powerful with New microchip generating 'Qudits' - TrendinTech - July 8th, 2017
- Quantum Computing Record Broken - Wall Street Pit - July 8th, 2017
- Alkermes and IBM's quantum computing. Who'll be the big winner? Malcolm Berko - Durham Herald Sun - July 6th, 2017
- Qudits: The Real Future of Quantum Computing? - IEEE Spectrum - IEEE Spectrum - July 1st, 2017
- Google to Achieve "Supremacy" in Quantum Computing by the End of 2017 - Big Think - July 1st, 2017
- Quantum Computing Becomes More Accessible - Scientific American - July 1st, 2017
- Tektronix AWG Pulls Test into Era of Quantum Computing - Electronic Design - June 2nd, 2017
- Toward mass-producible quantum computers | MIT News - MIT News - June 2nd, 2017
- Purdue, Microsoft Partner On Quantum Computing Research | WBAA - WBAA - June 2nd, 2017
- IBM boosts power of quantum computing processors as it lays ... - www.computing.co.uk - May 22nd, 2017
- IBM makes leap in quantum computing power - ITworld - May 22nd, 2017
- The Bizarre Quantum Test That Could Keep Your Data Secure - WIRED - May 18th, 2017
- Molecular magnets closer to application in quantum computing - Next Big Future - May 15th, 2017
- Inside Microsoft's 'soup to nuts' quantum computing ramp-up - Computerworld Australia - April 29th, 2017
- Quantum computing is about to disrupt the government contracts market - Bloomberg Government (blog) - April 22nd, 2017
- Scientists: We Have Detected the Existence of a Fundamentally New State of Matter - Futurism - April 22nd, 2017
- What Sorts Of Problems Are Quantum Computers Good For? - Forbes - April 22nd, 2017
- quantum computing - WIRED UK - April 22nd, 2017
- What is Quantum Computing? Webopedia Definition - March 18th, 2017
- Here Is Everything You Need to Know About Quantum Computers - Interesting Engineering - March 18th, 2017
- Quantum Computing Market Forecast 2017-2022 | Market ... - March 18th, 2017
- Mathematician breaks down how to defend against quantum ... - Phys.Org - February 28th, 2017