New colored protective coatings offer the same corrosion and wear protection as colorless coatings while their colouration opens new opportunities. Red could for instance be used as a warning color on surfaces which can get very hot. The new possibilities from combining protection and color in such coatings will be demonstrated by INM – Leibniz Institute for New Materials at this year’s Hannover Fair from 13 to 17 April as an exhibitor at the leading Research & Technology trade fair (stand B46 in hall 2). “Incorporating colored pigments in nanocomposites make coatings possible which are not only protective but also deliver additional visual information via their colouration,” explains Peter William de Oliveira, head of the IZI - Innovation Center INM. A protective coating for surfaces of ovens, chimneys or certain automotive parts could be colored red for instance. So such parts would not only be protected from corrosion, wear and oxidation but at the same time also be distinctive to the consumer by virtue of their color To create a full red shade without brown content, INM researchers are currently working on ceramic particles with red pigments free from iron oxide. Chemical compounds previously used were not very suitable for such applications. “Organic compounds do make for very nice reds – but they are unsuitable for such protective coatings, since organics do not survive high temperatures,” explains the physicist de Oliveira, “Iron oxides do withstand high temperatures when used as coloring particles for reds, but do not give full reds.” Black colored coatings with a thickness of two to five micrometers can withstand temperatures up to 900 degrees Celsius, but also coatings with a reddish brown color with resistance can endure up to 500 degrees Celsius. INM researchers are also developing protective coatings using blue and green pigments. Current developments at INM enable the use of these colored glass-ceramic layers on metals and glasses. The pigments are incorporated in sol-gel nanocomposites and applied by dipping or spraying.
Novel nanocomposite coatings combine protection with colour effects
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A first glimpse inside a macroscopic quantum state
In a recent study published in ("Macroscopic quantum state analyzed particle by particle"), the research group led by ICREA Prof at ICFO Morgan Mitchell has detected, for the first time, entanglement among individual photon pairs in a beam of squeezed light. 
This is an artist's impression of a beam of entangled photons. (Image: ICFO) Quantum entanglement is always related to the microscopic world, but it also has striking macroscopic effects, such as the squeezing of light or superconductivity, a physical phenomenon that allows high-speed trains to levitate. Squeezed light is not physically compressed but it is it manipulated in such a way that one of its properties is super well defined, for example its polarization. Compared with normal light, laser light, composed of independent photons, has an extremely small but nonzero polarization uncertainty. This uncertainty or "quantum noise" is directly linked to the existence of photons, the smallest energy quanta of light. Now, squeezed light has an uncertainty that is farther below this level. Therefore, in optical communications, squeezed light can help transmit much weaker signals with the same signal to noise ratio and the same light power. It can also be used to distribute secret keys to two distant parties through quantum cryptography. Although it has long been believed that many macroscopic phenomena are caused by large-scale entanglement, up to now, this link has only been proposed theoretically. On the other hand, current computer simulations of entangled particles have not been able to help discern any new properties regarding this relationship since the memory and processor time required grow exponentially with the number of entangled particles, thus limiting the studies to only a few particles. Albeit these issues, spin-squeezing experiments have been able to claim the observation of many entangled atoms, but these claims are indirect since they have measured the macroscopic properties and used theory to infer the entanglement. ICREA Prof at ICFO Morgan Mitchell comments, "I am continually amazed by quantum mechanics. When the theoretical predictions came out, saying that there should be a sea of entangled particles inside a squeezed state, I was floored. I knew we had to do an experiment to see this up close". Now for the first time, ICFO scientists have been able to directly and experimentally confirm this link. To do so, they fabricated a beam of squeezed light, predicted to consist almost entirely of entangled photons. Then they extracted a small number of photons at random and measured their quantum state, in particular the joint polarization state of photon pairs. After overcoming many experimental obstacles, they found, in agreement with theoretical predictions, that any two photons near each other are entangled. By changing the density of the beam, they also observed effects of entanglement monogamy, where particles can be strongly entangled only if they have few entanglement partners. Federica Beduini states that "the experiment was terribly difficult; we had to combine squeezing with entangled-photon detection. There were many unsolved problems. We had to invent many things, like super-narrow optical filters, just to make the experiment possible". The results of this study show promising advances for other macroscopic many-body systems and quantum gases such as Bose-Einstein condensates for the future study of superconductivity and superfluidity, optical communications, or the research and development of qubits for quantum computing.
This is an artist's impression of a beam of entangled photons. (Image: ICFO) Quantum entanglement is always related to the microscopic world, but it also has striking macroscopic effects, such as the squeezing of light or superconductivity, a physical phenomenon that allows high-speed trains to levitate. Squeezed light is not physically compressed but it is it manipulated in such a way that one of its properties is super well defined, for example its polarization. Compared with normal light, laser light, composed of independent photons, has an extremely small but nonzero polarization uncertainty. This uncertainty or "quantum noise" is directly linked to the existence of photons, the smallest energy quanta of light. Now, squeezed light has an uncertainty that is farther below this level. Therefore, in optical communications, squeezed light can help transmit much weaker signals with the same signal to noise ratio and the same light power. It can also be used to distribute secret keys to two distant parties through quantum cryptography. Although it has long been believed that many macroscopic phenomena are caused by large-scale entanglement, up to now, this link has only been proposed theoretically. On the other hand, current computer simulations of entangled particles have not been able to help discern any new properties regarding this relationship since the memory and processor time required grow exponentially with the number of entangled particles, thus limiting the studies to only a few particles. Albeit these issues, spin-squeezing experiments have been able to claim the observation of many entangled atoms, but these claims are indirect since they have measured the macroscopic properties and used theory to infer the entanglement. ICREA Prof at ICFO Morgan Mitchell comments, "I am continually amazed by quantum mechanics. When the theoretical predictions came out, saying that there should be a sea of entangled particles inside a squeezed state, I was floored. I knew we had to do an experiment to see this up close". Now for the first time, ICFO scientists have been able to directly and experimentally confirm this link. To do so, they fabricated a beam of squeezed light, predicted to consist almost entirely of entangled photons. Then they extracted a small number of photons at random and measured their quantum state, in particular the joint polarization state of photon pairs. After overcoming many experimental obstacles, they found, in agreement with theoretical predictions, that any two photons near each other are entangled. By changing the density of the beam, they also observed effects of entanglement monogamy, where particles can be strongly entangled only if they have few entanglement partners. Federica Beduini states that "the experiment was terribly difficult; we had to combine squeezing with entangled-photon detection. There were many unsolved problems. We had to invent many things, like super-narrow optical filters, just to make the experiment possible". The results of this study show promising advances for other macroscopic many-body systems and quantum gases such as Bose-Einstein condensates for the future study of superconductivity and superfluidity, optical communications, or the research and development of qubits for quantum computing.Frustration produces a quantum playground
The construction of model quantum systems or simulators that can reveal hidden insights into other, less accessible quantum states requires paying attention to interactions normally overlooked by most theories, finds a RIKEN-led study ("Microscopic Model Calculations for the Magnetization Process of Layered Triangular-Lattice Quantum Antiferromagnets"). The research team has uncovered evidence of a weak force in a quantum simulator prototype that can answer questions about phase transitions involving Heisenberg's uncertainty principle and supersolids — matter with both superfluid and crystalline order that behaves like a viscosity-free liquid. 
A new type of quantum state that forms between neighboring spin clusters in layered triangular-lattice magnets is sensitive enough to act as a quantum simulator — a probe of quantum behavior in other materials. (Image: Giacomo Marmorini, RIKEN Condensed Matter Theory Laboratory) One promising quantum simulator is a class of insulating crystals known as triangular-lattice antiferromagnets (TLAFs). These compounds feature sheets of magnetic atoms, each containing single unpaired spin states, bonded into perfect triangular lattices. The triangular geometry prevents the magnetic spins from finding their most energetically stable state, resulting in a ‘frustrated’ system that makes TLAFs superb probes of phase transitions brought on by quantum fluctuations. The newly found cobalt-based material Ba3CoSb2O9 appears to hold the most promise among TLAFs because it forms a nearly perfect triangular crystal with relatively simple magnetic interactions. Recent experimental measurements of Ba3CoSb2O9 single crystals, however, have revealed a peculiar magnetization anomaly: a sign of extra quantum spin states under high magnetic field that should not exist, according to most theories. Giacomo Marmorini and Ippei Danshita from RIKEN with Daisuke Yamamoto from Waseda University set out to solve this problem through ‘microscopic model’ theoretical calculations. This approach divides the TLAF lattice into multi-atom, triangular clusters that have the same equilibrium properties. By scaling from a minimal three-atom cluster to a near-infinite TLAF sheet, the team calculated how quantum effects emerged under different conditions of interacting spins. To make their model more realistic, they also included three-dimensional interactions between adjacent Ba3CoSb2O9 sheets. Numerical simulations revealed that the inclusion of interlayer coupling was crucial: the weak forces between sandwiched sheets disclosed another quantum phase transition that eluded traditional two-dimensional modeling (Fig. 1). “This might not seem intuitive, because interlayer coupling is more than an order of magnitude smaller than other forces in the plane,” says Marmorini. “But our work shows that ignoring such effects can yield results very distant from reality.” The scientists believe that their results could be useful for measuring the ‘critical exponents’ that define the behavior of substances such as supersolids. “For frustrated quantum systems, critical exponents cannot be calculated directly, even with our numerical methods,” notes Marmorini. “However, using Ba3CoSb2O9 as a quantum simulator could give unprecedented confirmation of these fundamental ideas.”
A new type of quantum state that forms between neighboring spin clusters in layered triangular-lattice magnets is sensitive enough to act as a quantum simulator — a probe of quantum behavior in other materials. (Image: Giacomo Marmorini, RIKEN Condensed Matter Theory Laboratory) One promising quantum simulator is a class of insulating crystals known as triangular-lattice antiferromagnets (TLAFs). These compounds feature sheets of magnetic atoms, each containing single unpaired spin states, bonded into perfect triangular lattices. The triangular geometry prevents the magnetic spins from finding their most energetically stable state, resulting in a ‘frustrated’ system that makes TLAFs superb probes of phase transitions brought on by quantum fluctuations. The newly found cobalt-based material Ba3CoSb2O9 appears to hold the most promise among TLAFs because it forms a nearly perfect triangular crystal with relatively simple magnetic interactions. Recent experimental measurements of Ba3CoSb2O9 single crystals, however, have revealed a peculiar magnetization anomaly: a sign of extra quantum spin states under high magnetic field that should not exist, according to most theories. Giacomo Marmorini and Ippei Danshita from RIKEN with Daisuke Yamamoto from Waseda University set out to solve this problem through ‘microscopic model’ theoretical calculations. This approach divides the TLAF lattice into multi-atom, triangular clusters that have the same equilibrium properties. By scaling from a minimal three-atom cluster to a near-infinite TLAF sheet, the team calculated how quantum effects emerged under different conditions of interacting spins. To make their model more realistic, they also included three-dimensional interactions between adjacent Ba3CoSb2O9 sheets. Numerical simulations revealed that the inclusion of interlayer coupling was crucial: the weak forces between sandwiched sheets disclosed another quantum phase transition that eluded traditional two-dimensional modeling (Fig. 1). “This might not seem intuitive, because interlayer coupling is more than an order of magnitude smaller than other forces in the plane,” says Marmorini. “But our work shows that ignoring such effects can yield results very distant from reality.” The scientists believe that their results could be useful for measuring the ‘critical exponents’ that define the behavior of substances such as supersolids. “For frustrated quantum systems, critical exponents cannot be calculated directly, even with our numerical methods,” notes Marmorini. “However, using Ba3CoSb2O9 as a quantum simulator could give unprecedented confirmation of these fundamental ideas.”
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