Phys.org news tagged with:quantum measurement
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en-usPhys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.Turning ions into quantum catsIn Schrödinger's famous thought experiment, a cat seems to be both dead and alive—an idea that strains credulity. These days, cats still don't act this way, but physicists now regularly create analogues of Schrödinger's cat in the lab by smearing the microscopic quantum world over macroscopic distances.
https://phys.org/news/2017-09-ions-quantum-cats.html
Quantum Physics Fri, 29 Sep 2017 07:52:24 ESTnews425890335Physicists measure complementary properties using quantum clones(Phys.org)—In quantum mechanics, it's impossible to precisely and simultaneously measure the complementary properties (such as the position and momentum) of a quantum state. Now in a new study, physicists have cloned quantum states and demonstrated that, because the clones are entangled, it's possible to precisely and simultaneously measure the complementary properties of the clones. These measurements, in turn, reveal the state of the input quantum system.
https://phys.org/news/2017-08-physicists-complementary-properties-quantum-clones.html
Quantum Physics Wed, 16 Aug 2017 10:40:04 ESTnews422028710Maxwell's demon extracts work from quantum measurement(Phys.org)—Physicists have proposed a new type of Maxwell's demon—the hypothetical agent that extracts work from a system by decreasing the system's entropy—in which the demon can extract work just by making a measurement, by taking advantage of quantum fluctuations and quantum superposition.
https://phys.org/news/2017-07-maxwell-demon-quantum.html
Quantum Physics Mon, 10 Jul 2017 09:30:01 ESTnews418873711'Quantum mechanical squeezing' enables quantum state atomic force microscopyBy taking advantage of a phenomenon known as "quantum mechanical squeezing," researchers have conceptually designed a new method of applying atomic force microscopy. Ali Passian of Oak Ridge National Laboratory and George Siopsis of the University of Tennessee introduced a novel method of making measurements in a paper published in Physical Review A.
https://phys.org/news/2017-05-quantum-mechanical-enables-state-atomic.html
Quantum Physics Wed, 03 May 2017 07:01:42 ESTnews413013693More reliable way to produce single photonsPhysicists at the University of Bath have developed a technique to more reliably produce single photons that can be imprinted with quantum information.
https://phys.org/news/2016-11-reliable-photons.html
Optics & Photonics Thu, 24 Nov 2016 11:03:01 ESTnews399207769Taking statistics to the quantum domain(Phys.org)—The change point problem is a concept in statistics that pops up in a wide variety of real-world situations, from stock markets to protein folding. The idea is to detect the exact point at which a sudden change has occurred, which could indicate, for example, the trigger of a financial crisis or a misfolded protein step.
https://phys.org/news/2016-11-statistics-quantum-domain.html
Quantum Physics Wed, 09 Nov 2016 09:30:01 ESTnews397881932Physicists retrieve 'lost' information from quantum measurements(Phys.org)—Typically when scientists make a measurement, they know exactly what kind of measurement they're making, and their purpose is to obtain a measurement outcome. But in an "unrecorded measurement," both the type of measurement and the measurement outcome are unknown.
https://phys.org/news/2016-09-physicists-lost-quantum.html
Quantum Physics Mon, 19 Sep 2016 09:40:02 ESTnews393494958Researchers build quantum sensors based on single solid-state spins(Phys.org)—A team of researchers with members from the Netherlands, Australia, and the U.K. has developed a new way to build an extremely sensitive magnetic sensor. As they describe in their paper published in the journal Nature Nanotechnology, their sensors are based on sensing with a single electron spin using real-time adaptive measurements.
https://phys.org/news/2015-12-quantum-sensors-based-solid-state.html
Nanophysics Wed, 02 Dec 2015 09:10:02 ESTnews368264331Getting the measure of matterPeter Rohde and his collaborators develop big ideas – and a measure of corny humour – using photons, the smallest possible units of light. (Did you hear about the photon that walked into a hotel and the clerk asked for its luggage? The photon said, "I'm travelling light.")
https://phys.org/news/2015-06-getting-the-measure-of-matter.html
Quantum Physics Tue, 16 Jun 2015 08:50:01 ESTnews353658721Why do measurements of the gravitational constant vary so much?(Phys.org)—Newton's gravitational constant, G, has been measured about a dozen times over the last 40 years, but the results have varied by much more than would be expected due to random and systematic errors. Now scientists have found that the measured G values oscillate over time like a sine wave with a period of 5.9 years. It's not G itself that is varying by this much, they propose, but more likely something else is affecting the measurements.
https://phys.org/news/2015-04-gravitational-constant-vary.html
General Physics Tue, 21 Apr 2015 09:30:01 ESTnews348820415Quantum experiment verifies Einstein's 'spooky action at a distance'An experiment devised in Griffith University's Centre for Quantum Dynamics has for the first time demonstrated Albert Einstein's original conception of "spooky action at a distance" using a single particle.
https://phys.org/news/2015-03-quantum-einstein-spooky-action-distance.html
Quantum Physics Tue, 24 Mar 2015 06:00:01 ESTnews346353355Researchers describe the wavefunction of Schroedinger's catSchrödinger's cat highlights a long-standing dilemma in quantum mechanics: is the cat really alive and dead, or is the weirdness just in our head?
https://phys.org/news/2015-02-wavefunction-schroedinger-cat.html
Quantum Physics Tue, 03 Feb 2015 05:36:25 ESTnews342164128Are weak values quantum? Don't bet on it(Phys.org) —New work asserts that a key technique used to probe quantum systems may not be so quantum after all, according to Perimeter postdoctoral researcher Joshua Combes and his colleague Christopher Ferrie.
https://phys.org/news/2014-09-weak-values-quantum-dont.html
Quantum Physics Wed, 24 Sep 2014 11:18:38 ESTnews330776308New technique uses fraction of measurements to efficiently find quantum wave functionsThe result of every possible measurement on a quantum system is coded in its wave function, which until recently could be found only by taking many different measurements of a system and estimating a wave function that best fit all those measurements. Just two years ago, with the advent of a technique called direct measurement, scientists discovered they could reliably determine a system's wave function by "weakly" measuring one of its variables (e.g. position) and "strongly" measuring a complementary variable (momentum). Researchers at the University of Rochester have now taken this method one step forward by combining direct measurement with an efficient computational technique.
https://phys.org/news/2014-08-technique-fraction-efficiently-quantum-functions.html
Quantum Physics Thu, 28 Aug 2014 09:35:37 ESTnews328437320Researchers find nondestructive method to study quantum wave systemsThe laws of classical physics that describe the world around us can be very different from those of the quantum world. At the quantum level, particles can behave more like waves that can pass through each other and display properties very different from those of classical objects. However, one of the complexities of quantum physics is that any experimental measurement disturbs, or even destroys, these wave-like quantum states, making it difficult to reach a better understanding of such states through experiments.
https://phys.org/news/2014-05-nondestructive-method-quantum.html
Quantum Physics Fri, 16 May 2014 09:20:02 ESTnews319450051Peeking into Schrodinger's box: Direct measurement shows potential for quantum informationUntil recently measuring a 27-dimensional quantum state would have been a time-consuming, multistage process using a technique called quantum tomography, which is similar to creating a 3D image from many 2D ones. Researchers at the University of Rochester have been able to apply a recently developed, alternative method called direct measurement to do this in a single experiment with no post-processing. The work is of interest because fast, accurate and efficient methods for characterizing high-dimensional states like this could be central in developing high security quantum communications systems, as well as to probe our fundamental understanding of quantum mechanics.
https://phys.org/news/2014-01-peeking-schrodinger-potential-quantum.html
Quantum Physics Mon, 20 Jan 2014 05:00:01 ESTnews309373273Physicists aim to make transition to quantum world visibleTheoretical physicist Frank Wilhelm-Mauch and his research team at Saarland University have developed a mathematical model for a type of microscopic test lab that could provide new and deeper insight into the world of quantum particles. The new test system will enable the simultaneous study of one hundred light quanta (photons) and their complex quantum mechanical relationships ("quantum entanglement") – a far greater number than was previously possible. The researchers hope to gain new insights that will be of relevance to the development of quantum computers. They are the first group worldwide to undertake such studies using a so-called "metamaterial", a specially constructed lattice of nanostructures that is able to refract light more strongly than existing natural materials.
https://phys.org/news/2013-10-physicists-aim-transition-quantum-world.html
Quantum Physics Fri, 25 Oct 2013 11:46:43 ESTnews301920383Classical physics shown to be equal to quantum theory when it comes to unusual experiments with light beamsQuantum mechanics provides such a different description of the world compared to classical physics that even Albert Einstein had problems comprehending the implications of the theory. However, sometimes the predictions attributed to quantum-mechanical effects alone actually conform to the framework and predictions of classical physics. Franco Nori, Konstantin Bliokh and colleagues from the RIKEN Center for Emergent Matter Science have now derived a classical theory explanation for a light beam experiment previously explained only through complex quantum-mechanical arguments.
https://phys.org/news/2013-10-classical-physics-shown-equal-quantum.html
Quantum Physics Fri, 25 Oct 2013 07:20:01 ESTnews301903531Quantum measurement carries information even when the measurement outcome is unread(Phys.org) —Some tasks that are impossible in classical systems can be realized in quantum systems. This fact is exemplified by a new protocol that highlights an important difference between classical and quantum measurements. In classical mechanics, performing a measurement without reading the measurement outcome does not carry any information and is therefore equivalent to not performing the measurement at all. But in the new protocol, a quantum measurement that is performed but not read can carry information because the information can be encoded in the choice of the type of measurement that was performed.
https://phys.org/news/2013-08-quantum-outcome-unread.html
Quantum Physics Tue, 27 Aug 2013 09:00:01 ESTnews296803526Physicist disentangles 'Schrodinger's cat' debatePhysicist Art Hobson has offered a solution, within the framework of standard quantum physics, to the long-running debate about the nature of quantum measurement.
https://phys.org/news/2013-08-physicist-disentangles-schrodinger-cat-debate.html
Quantum Physics Mon, 26 Aug 2013 14:06:54 ESTnews296744801'Listening' to black holes form with gravity wavesNew technology that breaks the quantum measurement barrier has been developed to detect the gravity waves first predicted by Einstein in 1916.
https://phys.org/news/2013-08-black-holes-gravity.html
Optics & Photonics Fri, 16 Aug 2013 10:10:02 ESTnews295863849Squeezed light produced using silicon micromechanical systemOne of the many counterintuitive and bizarre insights of quantum mechanics is that even in a vacuum—what many of us think of as an empty void—all is not completely still. Low levels of noise, known as quantum fluctuations, are always present. Always, that is, unless you can pull off a quantum trick. And that's just what a team led by researchers at the California Institute of Technology (Caltech) has done. The group has engineered a miniature silicon system that produces a type of light that is quieter at certain frequencies—meaning it has fewer quantum fluctuations—than what is usually present in a vacuum.
https://phys.org/news/2013-08-silicon-micromechanical.html
Quantum Physics Wed, 07 Aug 2013 13:00:06 ESTnews295093649Closing in on Einstein's window to the universe(Phys.org) —Nearly a century after the world's greatest physicist, Albert Einstein, first predicted the existence of gravitational waves, a global network of gravitational wave observatories has moved a step closer to detecting the faint radiation that could lead to important new discoveries in our universe.
https://phys.org/news/2013-08-einstein-window-universe.html
Optics & Photonics Thu, 01 Aug 2013 08:10:01 ESTnews294562620Tetrapod nanocrystals light the way to stronger polymersFluorescent tetrapod nanocrystals could light the way to the future design of stronger polymer nanocomposites. A team of researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) has developed an advanced opto-mechanical sensing technique based on tetrapod quantum dots that allows precise measurement of the tensile strength of polymer fibers with minimal impact on the fiber's mechanical properties.
https://phys.org/news/2013-07-tetrapod-nanocrystals-stronger-polymers.html
Nanophysics Mon, 29 Jul 2013 13:22:20 ESTnews294322926Physicists publish solution to the quantum measurement problem(Phys.org) —Quantum mechanics is a highly successful theory, but its interpretation has still not been settled. In their recent opus magnum, Theo Nieuwenhuizen (Institute of Physics, UvA) and colleagues claim to have found a solution to the so-called quantum measurement problem.
https://phys.org/news/2013-07-physicists-publish-solution-quantum-problem.html
Quantum Physics Wed, 17 Jul 2013 06:50:01 ESTnews293256967Most experiments that claim to show the quantum Zeno paradox fall short, study says(Phys.org) —By their very nature, unstable particles will eventually decay, some faster than others. But according to the quantum Zeno paradox (QZP), an unstable particle that is observed continuously has been said to never decay. Though counterintuitive, this effect has been claimed to show up experimentally in numerous ways. Now in a new study, physicist Peter Toschek at the University of Hamburg in Hamburg, Germany, has argued that most of these experiments do not provide sufficient evidence of the QZP. By identifying the sufficient conditions necessary for proving the QZP, he confirms the validity of the paradox while probing deeper into its origins.
https://phys.org/news/2013-06-quantum-zeno-paradox-fall-short.html
Quantum Physics Wed, 05 Jun 2013 09:00:01 ESTnews289632237More precision from less predictability: A new quantum trade-offAn important advance in the quantitative understanding and experimental verification of complementarity; arguably the most important foundational principle of quantum mechanics.
https://phys.org/news/2013-05-precision-quantum-trade-off.html
Quantum Physics Wed, 29 May 2013 17:00:02 ESTnews289058936Uncertainty revisited: Novel tradeoffs in quantum measurement(Phys.org) —There is, so to speak, uncertainty about uncertainty – that is, over the interpretation of how Heisenberg's uncertainty principle describes the extent of disturbance to one observable when measuring another. More specifically, the confusion is between the fact that, as Heisenberg first intuited, the measurement of one observable on a quantum state necessarily disturbs another incompatible observable, and the fact that on the other hand the indeterminacy of the outcomes when either one or the other observable is measured is bounded. Recently, Dr. Cyril Branciard at The University of Queensland precisely quantified the former by showing how it is possible to approximate the joint measurement of two observables, albeit with the introduction of errors with respect to the ideal measurement of each. Moreover, the scientist characterized the disturbance of an observable induced by the approximate measurement of another one, and derived a stronger error-disturbance relation for this scenario.
https://phys.org/news/2013-05-uncertainty-revisited-tradeoffs-quantum.html
Quantum Physics Tue, 28 May 2013 09:00:01 ESTnews288948339Physicists present a non-destructive technique for measuring at the atomic scaleImproving our understanding of the human brain, gathering insights into the origin of our universe through the detection of gravitational waves, or optimizing the precision of GPS systems- all are difficult challenges to master because they require the ability to visualize highly fragile elements, which can be terminally damaged by any attempt to observe them. Now, quantum physics has provided a solution. In an article published in Nature Photonics, researchers at the Institute of Photonic Sciences (ICFO) report the observation of a highly fragile and volatile body through a new quantum-mechanical measurement technique.
https://phys.org/news/2013-05-physicists-non-destructive-technique-atomic-scale.html
Optics & Photonics Sun, 12 May 2013 17:03:47 ESTnews286955848Cold atoms for quantum technologyResearchers from the National Physical Laboratory, University of Strathclyde, Imperial College London and University of Glasgow have developed a portable way to produce ultracold atoms for quantum technology and quantum information processing. Their research has been published in the journal Nature Nanotechnology, where it is featured on the front cover.
https://phys.org/news/2013-05-cold-atoms-quantum-technology.html
Quantum Physics Wed, 08 May 2013 09:20:08 ESTnews287223595