Tag Archives | Quantum Physics

Training Schrodinger’s cat: Controlling the quantum properties of light

Zeno cat. A Zeno cat refers to non-classical states of light created by shining a cavity on resonance while it is forbidden to access a given energy level. The name originates from the Zeno effect, which can similarly prevent an energy level from being occupied by the sole fact of measuring its occupation frequently. The cat comes from the similarity of such a state with a Schrödinger cat state of light: a superposition between two classical states of light. The Zeno cat figure corresponds to the study’s experimental design. Credit: Benjamin Huard.

Zeno cat. A Zeno cat refers to non-classical states of light created by shining a cavity on resonance while it is forbidden to access a given energy level. The name originates from the Zeno effect, which can similarly prevent an energy level from being occupied by the sole fact of measuring its occupation frequently. The cat comes from the similarity of such a state with a Schrödinger cat state of light: a superposition between two classical states of light. The Zeno cat figure corresponds to the study’s experimental design. Credit: Benjamin Huard.

Stuart Mason Dambrot via Phys.org:

(Phys.org)—Constructing quantum computers and other quantum devices requires the ability to leverage quantum properties such as superposition and entanglement – but these effects are fragile and therefore hard to maintain. Recently, scientists at Ecole Normale Supérieure in Paris demonstrated a novel method for controlling the quantum properties of light by probing a superconducting circuit in a cavity with microwave photons to control the energy levels that photon quanta can occupy.

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Reality Doesn’t Exist Until You Look At It

So how does this affect Schroedinger’s cat, quantum disinfonauts? From the Independent:

Reality doesn’t exist until it’s measured, at least for very small things, new research has found.

Schroedingers cat film.svg

“Schroedingers cat film” by Christian Schirm (CC)

By replicating a famous experiment where an object is given a choice for how to behave, physicists found that the object doesn’t actually make its decision until it is seen. The finding proves one of the central parts of quantum theory, a branch of science that has been applied to make much of our modern technology.

Scientists gave an object a chance either to act like a wave or a particle, and looked to find out when the decision was made. While one might expect that it is either one or the other, quantum physics predicts that it will only act one way or the other when it is measured, after it has decided — and that was confirmed by the experiment.

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Quantum Physics Just Got Less Complicated: Wave-Particle Duality and Quantum Uncertainty Are Same Thing

Quantum physics says that particles can behave like waves, and vice versa. Researchers have now shown that this 'wave-particle duality' is simply the quantum uncertainty principle in disguise. Credit: Timothy Yeo / CQT, National University of Singapore; CC-BY

“Quantum physics says that particles can behave like waves, and vice versa. Researchers have now shown that this ‘wave-particle duality’ is simply the quantum uncertainty principle in disguise.”

Credit: Timothy Yeo / CQT, National University of Singapore; CC-BY

Via ScienceDaily:

Here’s a nice surprise: quantum physics is less complicated than we thought. An international team of researchers has proved that two peculiar features of the quantum world previously considered distinct are different manifestations of the same thing. The result is published 19 December in Nature Communications.

Patrick Coles, Jedrzej Kaniewski, and Stephanie Wehner made the breakthrough while at the Centre for Quantum Technologies at the National University of Singapore. They found that ‘wave-particle duality’ is simply the quantum ‘uncertainty principle’ in disguise, reducing two mysteries to one.

“The connection between uncertainty and wave-particle duality comes out very naturally when you consider them as questions about what information you can gain about a system.

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China to build global quantum communication network in 2030

jazbeck (CC by-sa 2.0)

jazbeck (CC by-sa 2.0)

via Space Daily:

China will build a global quantum communication network by 2030, said a leading Chinese quantum physicist on Sunday.

“China’s quantum information science and technology is developing very fast and China leads in some areas in this field,” said Pan Jianwei, a Chinese quantum scientist and professor at the University of Science and Technology of China.

The field of quantum communication, the science of transmitting quantum states from one place to another, grabbed global attention in recent years after the discovery of quantum cryptography, which is described as a way of creating “unbreakable” messages.

China will achieve Asia-Europe intercontinental quantum key distribution in 2020 and build a global quantum communication network in 2030, said Pan at the 2014 International Conference on Quantum Communication, Measurement and Computing,which opened Sunday in east China’s Hefei city.

Read More: http://www.spacedaily.com/reports/China_to_build_global_quantum_communication_network_in_2030_999.html

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Quantum State: It’s A Thang!

Quantum bouncerPhysicists are finally plucking up the courage to think that quantum mechanics might actually represent reality, and is not just a useful theory, suggests Chris Lee at Ars Technica:

At the very heart of quantum mechanics lies a monster waiting to consume unwary minds. This monster goes by the name The Nature of Reality™. The greatest of physicists have taken one look into its mouth, saw the size of its teeth, and were consumed. Niels Bohr denied the existence of the monster after he nonchalantly (and very quietly) exited the monster’s lair muttering “shut up and calculate.” Einstein caught a glimpse of the teeth and fainted. He was reportedly rescued by Erwin Schrödinger at great personal risk, but neither really recovered from their encounter with the beast.

The upshot is that we had a group of physicists and philosophers who didn’t believe that quantum mechanics represents reality but that it was all we could see of some deeper, more fundamental theory.

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More Evidence That Plants Get Their Energy Through Quantum Entanglement

fern plantAs top human scientists dream of someday creating a quantum computer, are we lagging far behind plants? io9 reports:

Biophysicists theorize that plants tap into the eerie world of quantum entanglement during photosynthesis. Evidence to date has been purely circumstantial, but now, scientists have discovered a feature of plants that cannot be explained by classical physics.

In a way, they’re like mini-quantum computers capable of scanning all possible options in order to choose the most efficient paths or solutions. For plants, this means the ability to make the most of the energy they receive and then deliver that energy from leaves with near perfect efficiency.

The going theory is that plants have light-gathering macromolecules in their cells that can transfer energy via molecular vibrations — vibrations that have no equivalents in classical physics.

In the new study, UCL researchers identified a specific feature in biological systems that can only be predicted by quantum physics.

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New Compelling Evidence Suggesting The Universe Is A Hologram

hologramIn existential news, Tupac isn’t the only one who may merely be a flat holographic projection. Via Nature:

A team of physicists has provided some of the clearest evidence yet that our Universe could be just one big projection.

In 1997, theoretical physicist Juan Maldacena proposed an audacious model of the Universe in which gravity arises from infinitesimally thin, vibrating strings. The mathematically intricate world of strings, which exist in nine dimensions of space plus one of time, would be merely a hologram: the real action would play out in a simpler, flatter, single dimensional cosmos where there is no gravity.

Maldacena’s idea thrilled physicists because it solved apparent inconsistencies between quantum physics and Einstein’s theory of gravity.

In two papers posted on the arXiv repository, Yoshifumi Hyakutake of Ibaraki University in Japan and his colleagues now provide, if not an actual proof, at least compelling evidence that Maldacena’s conjecture is true.

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Do We Live in the Matrix?

The.Matrix.glmatrix.2Zeeya Merali says that “tests could reveal whether we are part of a giant computer simulation — but the real question is if we want to know,” writing for Discover:

In the 1999 sci-fi film classic The Matrix, the protagonist, Neo, is stunned to see people defying the laws of physics, running up walls and vanishing suddenly. These superhuman violations of the rules of the universe are possible because, unbeknownst to him, Neo’s consciousness is embedded in the Matrix, a virtual-reality simulation created by sentient machines.

The action really begins when Neo is given a fateful choice: Take the blue pill and return to his oblivious, virtual existence, or take the red pill to learn the truth about the Matrix and find out “how deep the rabbit hole goes.”

Physicists can now offer us the same choice, the ability to test whether we live in our own virtual Matrix, by studying radiation from space.

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