Faster Than Speed of Light

The inside of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider. Rochester physicists working at the detector have observed spin entanglement between top quarks and top antiquarks persisting at long distances and high speeds. Credit: CERN




Researchers have confirmed that quantum entanglement persists between top quarks, the heaviest known fundamental particles.

Physicists have demonstrated quantum entanglement in top quarks and their antimatter partners, a discovery made at CERN. This finding extends the behavior of entangled particles to distances beyond the reach of light-speed communication and opens new avenues for exploring quantum mechanics at high energies.

An experiment by a group of physicists led by University of Rochester physics professor Regina Demina has produced a significant result related to quantum entanglement—an effect that Albert Einstein called “spooky action at a distance.”

Entanglement concerns the coordinated behavior of minuscule particles that have interacted but then moved apart. Measuring properties—like position or momentum or spin—of one of the separated pair of particles instantaneously changes the results of the other particle, no matter how far the second particle has drifted from its twin. In effect, the state of one entangled particle, or qubit, is inseparable from the other.       READ MORE...

Interior of Protons Entangled

If a photon carries too little energy, it does not fit inside a proton (left). A photon with sufficiently high energy is so small that it flies into the interior of a proton, where it 'sees' part of the proton (right). Maximum entanglement then becomes visible between the 'seen' and 'unseen' areas. Credit: IFJ PAN



Fragments of the interior of a proton have been shown by scientists from Mexico and Poland to exhibit maximum quantum entanglement. The discovery, already confronted with experimental data, allows us to suppose that in some respects the physics of the inside of a proton may have much in common not only with well-known thermodynamic phenomena, but even with the physics of... black holes.

Various fragments of the inside of a proton must be maximally entangled with each other, otherwise theoretical predictions would not agree with the data collected in experiments, it was shown in European Physical Journal C. 

The theoretical model (which extends the original proposal by physicists Dimitri Kharzeev and Eugene Levin) makes it possible to suppose that, contrary to current belief, the physics operating inside protons may be related to such concepts as entropy or temperature, which in turn may relate it to such exotic objects as black holes. 

The authors of the discovery are Dr. Martin Hentschinski from the Universidad de las Americas Puebla in Mexico and Dr. Krzysztof Kutak from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow, Poland.

The Mexican-Polish theorists analyzed the situation in which electrons are fired at protons. When an incoming electron carrying a negative electric charge approaches a positively charged proton, it interacts with it electromagnetically and deflects its path. 

Electromagnetic interaction means that a photon has been exchanged between the electron and the proton. The stronger the interaction, the greater the change in momentum of the photon and therefore the shorter the associated electromagnetic wave.  READ MORE...

Taking a Giant Leap

ORNL’s Joseph Lukens runs experiments in an optics lab. Credit: Jason Richards/ORNL, U.S. Dept. of Energy

Scientists' increasing mastery of quantum mechanics is heralding a new age of innovation. Technologies that harness the power of nature's most minute scale show enormous potential across the scientific spectrum, from computers exponentially more powerful than today's leading systems, sensors capable of detecting elusive dark matter, and a virtually unhackable quantum internet.

Researchers at the Department of Energy's Oak Ridge National Laboratory, Freedom Photonics and Purdue University have made strides toward a fully quantum internet by designing and demonstrating the first ever Bell state analyzer for frequency bin coding.

Their findings were published in Optica.

Before information can be sent over a quantum network, it must first be encoded into a quantum state. This information is contained in qubits, or the quantum version of classical computing "bits" used to store information, that become entangled, meaning they reside in a state in which they cannot be described independently of one another.

Entanglement between two qubits is considered maximized when the qubits are said to be in "Bell states."

Measuring these Bell states is critical to performing many of the protocols necessary to perform quantum communication and distribute entanglement across a quantum network. And while these measurements have been done for many years, the team's method represents the first Bell state analyzer developed specifically for frequency bin coding, a quantum communications method that harnesses single photons residing in two different frequencies simultaneously.  READ MORE...

New programming Language

While the nascent field of quantum computing can feel flashy and futuristic, quantum computers have the potential for computational breakthroughs in classically unsolvable tasks, like cryptographic and communication protocols, search, and computational physics and chemistry. Photo: Graham Carlow/IBM


Programming quantum computers require awareness of entanglement, the phenomenon in which measurement outcomes of qubits are correlated. Entanglement can determine the correctness of algorithms and the suitability of programming patterns.

Entangled qubits give rise to Einstein’s characterization of “spooky action at a distance.” But that potency is equal parts a source of weakness. While programming, discarding one qubit without being aware of its entanglement with one more qubit can obliterate the information put away in the other, endangering the accuracy of the program.

MIT scientists have created their programming language for quantum computing. This new language, called Twist, can describe and verify which pieces of data are entangled in a quantum program.

To create this new language, scientists used a concept called Purity. It enforces the absence of entanglement and results in more intuitive programs, with ideally fewer bugs.

Charles Yuan, an MIT Ph.D. student in electrical engineering and computer science and the lead author of a new paper about Twist, said, “Our language Twist allows a developer to write safer quantum programs by explicitly stating when a qubit must not be entangled with another. Because understanding quantum programs requires understanding entanglement, we hope that Twist paves the way to languages that make the unique challenges of quantum computing more accessible to programmers.”  READ MORE...

A Quantum Reality