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Archive for the ‘quantum physics’ category: Page 700

Feb 21, 2017

Photon Gun Could Further Development of Photonic Quantum Network

Posted by in categories: nanotechnology, quantum physics

A photonic nanostructure for constructing quantum photonic circuits for quantum networks has been developed, which could impact the optics and photoni.

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Feb 21, 2017

NSCI Seminar: Quantum Applications and Microsoft’s unique approach to Quantum Computing

Posted by in categories: chemistry, engineering, quantum physics, robotics/AI

Sharing in case folks would like to listen in.


Microsoft’s Station Q was founded in 2006. The focus of the team has always been topological quantum computing. By taking a full systems architecture approach, we have reached the point where we now able to start engineering a scalable quantum computer. The goal is to be able to solve major problems in areas of interest (e.g., Chemistry, Materials and Machine Learning). This talk will focus on the types of applications that we will be trying to solve as well as the unique approach to quantum computation that we’ve developed. For reference, see:

Current Approach: https://arxiv.org/abs/1610.05289 Chemistry Application: https://arxiv.org/abs/1605.03590 Other papers: https://arxiv.org/find/all/1/all:+wecker_d/0/1/0/all/0/1

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Feb 21, 2017

Quantum Entanglement is Just as Einstein Predicted

Posted by in categories: particle physics, quantum physics

I never doubt the theory.


We owe a lot to Einstein, and this week physicists have confirmed another of his theories by unraveling and proving that quantum entanglement does in fact exist. Under the standard quantum theory, nothing has a definitive state until it’s measured, and when two particles interact they become entangled. Being entangled means no longer do the particles have their probabilities but one that includes both particles together. Even though two photons become entangled, they can still travel light years apart from each other, but they will always remain linked.

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Feb 21, 2017

Shell-Dependent Photoluminescence Studies Provide Mechanistic Insights into the Off-Grey-On Transitions of Blinking Quantum Dots

Posted by in categories: materials, quantum physics

The majority of quantum dot (QD) blinking studies have used a model of switching between two distinct fluorescence intensity levels, “on” and “off”. However, a distinct intermediate intensity level has been identified in some recent reports – a so-called “grey” or “dim” state, which has brought this binary model into question. While this grey state has been proposed to result from the formation of a trion, it is still unclear under which conditions it is present in a QD. By performing shell-dependent blinking studies on CdSe QDs, we report that the populations of the grey state and the on state are strongly dependent on both the shell material and its thickness. We found that adding a ZnS shell did not result in a significant population of the grey state. Using ZnSe as the shell material resulted in a slightly higher population of the grey state, although it was still poorly resolved. However, adding a CdS shell resulted in the population of a grey state, which depended strongly on its thickness up to 5 ML. Interestingly, while the frequency of transitions to and from the grey state showed a very strong dependence on CdS shell thickness, the brightness of and the dwell time in the grey state did not. Moreover, we found that the grey state acts as an on-pathway intermediate state between on and off states, with the thickness of the shell determining the transition probability between them. We also identified two types of blinking behavior in QDs, one that showed long-lived but lower intensity on states and another that showed short-lived but brighter on states that also depended on the shell thickness. Intensity-resolved single QD fluorescence lifetime analysis was used to identify the relationship between the various exciton decay pathways and the resulting intensity levels. We used this data to propose a model in which multiple on, grey and off states exist whose equilibrium populations vary with time that give rise to the various intensity levels of single QDs, and which depends on shell composition and thickness.

View: PDF | PDF w/ Links.

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Feb 21, 2017

A.I. Machines Are Learning Quantum Physics And Solving Complex Problems On Their Own

Posted by in categories: particle physics, quantum physics, robotics/AI, supercomputing

In the past, traditional methods to understand the behavior of quantum interacting systems have worked well, but there are still many unsolved problems. To solve them, Giuseppe Carleo of ETH Zurich, Switzerland, used machine learning to form a variational approach to the quantum many-body problem.

Before digging deeper, let me tell you a little about the many-body problem. It deals with the difficulty of analyzing “multiple nontrivial relationships encoded in the exponential complexity of the many-body wave function.” In simpler language, it’s the study of interactions between many quantum particles.

If we take a look at our current computing power, modeling a wave function will need lot more powerful supercomputers. But, according to Carleo, the neural networks are pretty good at generalizing. Hence, they need only limited information to infer something. So, fiddling with this idea, Carleo and Matthias Troyer created a simple neural network to reconstruct such multi-body wave function.

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Feb 18, 2017

EmDrive: Chinese space agency to put controversial tech onto satellites ‘as soon as possible’

Posted by in categories: government, quantum physics, satellites

Chinese government confirms it has been funding EmDrive research since 2010 and believes in its benefits.

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Feb 16, 2017

All inherited diseases including cancer ‘could be cured in the next 20 years’

Posted by in categories: biotech/medical, genetics, quantum physics

Definitely yes on gene mutations; however, those where the disease has already appeared, or cancer that has occurred before will require another form of eradication/ prevention. And, that is where Quantum Biosystem technology will be effective in eliminating disease.


ALL inherited diseases could be cured within 20 years, a leading British expert claims.

It includes eradicating life-limiting conditions such as cystic fibrosis and Huntington’s disease.

Continue reading “All inherited diseases including cancer ‘could be cured in the next 20 years’” »

Feb 16, 2017

Revolutionary New Technique Visualizes Biomolecules Without Crystallization

Posted by in categories: particle physics, quantum physics

Quantum interpolation makes viewing Biomolecules at room temp. possible without freezing. This technique will enable more powerful sensors than we have ever had before.


In the latest issue of Proceedings of the National Academy of Sciences, researchers from MIT and Singapore University of Technology and Design are describing a new technique that may finally give life scientists a detailed view into many of the biomolecules they work with. These days, X-ray diffraction is typically used to see the structure of a molecule. But this requires crystallization, a process not all molecules, including many proteins, are unwilling to undergo.

The technology uses tiny diamond crystals that have a nitrogen atom in place of a single carbon atom. These so-called “nitrogen vacancy centers” make the crystals react to minute fluctuations of magnetic and electric fields surrounding them. They’re so sensitive that the spins of individual atoms of a nearby molecule affect them enough to be detected by an external device.

Continue reading “Revolutionary New Technique Visualizes Biomolecules Without Crystallization” »

Feb 16, 2017

Quantum non-Markovianity induced by Anderson localization

Posted by in categories: particle physics, quantum physics

Nice information on Quantum open systems via the existence of a functional relationship between a rigorous measure of quantum non–Markovian ity and the CCA localization. Sharing with my other QC R&D friends.


As discovered by P. W. Anderson, excitations do not propagate freely in a disordered lattice, but, due to destructive interference, they localise. As a consequence, when an atom interacts with a disordered lattice, one indeed observes a non-trivial excitation exchange between atom and lattice. Such non-trivial atomic dynamics will in general be characterised also by a non-trivial quantum information backflow, a clear signature of non–Markovian dynamics. To investigate the above scenario, we consider a quantum emitter, or atom, weakly coupled to a uniform coupled-cavity array (CCA). If initially excited, in the absence of disorder, the emitter undergoes a Markovian spontaneous emission by releasing all its excitation into the CCA (initially in its vacuum state). By introducing static disorder in the CCA the field normal modes become Anderson-localized, giving rise to a non–Markovian atomic dynamics. We show the existence of a functional relationship between a rigorous measure of quantum non–Markovian ity and the CCA localization. We furthermore show that the average non–Markovian ity of the atomic dynamics is well-described by a phenomenological model in which the atom is coupled, at the same time, to a single mode and to a standard — Markovian — dissipative bath.

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Feb 16, 2017

Finite-temperature scaling of trace distance discord near criticality in spin diamond structure

Posted by in categories: futurism, quantum physics

Nice research on finite temperatures and diamond structure spins.


Here the quantum criticality in the Ising-XXZ diamond structure at finite temperature have been studied by the trance distance discord calculations. Around the critical lines, the first-order derivative of the trace distance discord exhibits a maximal at a finite temperature and diverges under the thermodynamic limits T → 0. By analyzing the finite-temperature scaling behaviors, we show that the trace distance discord can detect exactly the quantum phase transition from the entangled state in ferrimagnetic phase to an unentangled state in ferrimagnetic phase or to an unentangled state in ferromagnetic phase. The results also show that the trace distance can distinguish the two kinds of transitions by consulting to the different finite-temperature scaling behaviors. As a comparison, we also study the behaviors of some other typical quantum correlations (e.g., concurrence, quantum discord and Hellinger distance) around the critical points, and the results state that the trance distance discord is more reliable than the others to spotlight the critical points for this Ising-XXZ diamond structure at finite temperatures.

Surely, this model system has three different critical phases, and it would be significant and challenging in the future to consider the multipartite quantum correlations which may grasp all these transitions. The bipartite quantum correlations imposed on this Ising-XXZ diamond structure, as studied in this work, can not detect the transition from UFI phase to UFM phase at finite temperature, an issue for future investigations.

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