Hole pocket-driven superconductivity and its universal features in the electron-doped cuprates

DNA as a perfect quantum computer based on the quantum physics principles

DNA is a complex multi-resolution molecule whose theoretical study is a challenge. Its intrinsic multiscale nature requires chemistry and quantum physics to understand the structure and quantum informatics to explain its operation as a perfect quantum computer. Here, we present theoretical results of DNA that allow a better description of its structure and the operation process in the transmission, coding, and decoding of genetic information. Aromaticity is explained by the oscillatory resonant quantum state of correlated electron and hole pairs due to the quantized molecular vibrational energy acting as an attractive force. The correlated pairs form a supercurrent in the nitrogenous bases in a single band π -molecular orbital ( π -MO). The MO wave function ( Φ ) is assumed to be the linear combination of the n constituent atomic orbitals. The central Hydrogen bond between Adenine (A) and Thymine (T) or Guanine (G) and Cytosine (C) functions like an ideal Josephson Junction. The approach of a Josephson Effect between two superconductors is correctly described, as well as the condensation of the nitrogenous bases to obtain the two entangled quantum states that form the qubit. Combining the quantum state of the composite system with the classical information, RNA polymerase teleports one of the four Bell states. DNA is a perfect quantum computer.

Point-Contact Spectroscopy in Bulk Samples of Electron-Doped Cuprate Superconductors

Point-contact spectroscopy was performed on bulk samples of electron-doped high temperature superconductor Nd2-xCexCuO4-δ. The samples were characterized using X-ray diffraction and scanning electron microscopy equipped with a wavelength-dispersive spectrometer and an electron backscatter diffraction detector. Samples with Ce content x = 0.15 showed the absence of spurious phases and randomly oriented grains, most of which had dimensions of approximately 220 µm2. The low-bias spectra in the tunneling regime, i.e., high-transparency interface, exhibited a gap feature at about ±5 meV and no zero-bias conductance, despite the random oriented grains investigated within our bulk samples, consistent with most of the literature data on oriented samples. High-bias conductance was also measured in order to obtain information on the properties of the barrier. A V-shape was observed in some cases, instead of the parabolic behavior expected for tunnel junctions.

Universal correlation of the superconducting transition temperature with the linear-in-T coefficient, electron packing parameter, and the numbers of valence and conduction electrons

A generic conductivity equation, developed in our previous work, is used to predict the universal superconducting transition temperature, T_c. Our prediction shows that T_c and the linear-in-T scattering coefficient, A₁, have a scaling relationship of T_c ∼ A₁^0.5, where A₁ comes from the empirical experimental equation ρ = ρ₀ + A₁T with ρ as the resistivity, which is consistent with recent experimental observations. However, our theory suggests that 1/ρ has a linear relationship with 1/T, rather than the empirical relationship between ρ and T postulated in the literature. The physical meaning of A₁ is made clear by the equations, and it is related to the electron packing parameter, α, the number of valence electrons per unit cell, the number of conduction electrons in the entire system, and the volume of the material under study, among others. In general, T_c increases with α and the number of valence electrons per unit cell, but decreases sharply with the number of conduction electrons. A ridge appears when α is around 30, suggesting that T_c may reach a maximum at this point. Our findings not only provide theoretical support for recent experimental observations but also offer insight into achieving high T_c by fine-tuning material properties and have broader implications for understanding superconductivity in a universal manner.

Normal-State Transport Properties of Infinite-Layer Sr1-xLaxCuO2 Electron-Doped Cuprates in Optimal- and Over-Doped Regimes

Transport properties of electron-doped cuprate Sr1−xLaxCuO2 thin films have been investigated as a function of doping. In particular, optimal- and over-doped samples were obtained by tuning the Sr:La stoichiometric ratio. Optimal-doped samples show a non-Fermi liquid behavior characterized by linear dependence of the resistivity from room temperature down to intermediate temperature (about 150–170 K). However, by approaching temperatures in the superconducting transition, a Fermi-liquid behavior-characterized by a T2-scaling law-was observed. Once established, the transition from a linear-T to a quadratic-T2 behavior was successfully traced back in over-doped samples, even occurring at lower temperatures. In addition, the over-doped samples show a crossover to a linear-T to a logarithmic dependence at high temperatures compatible with anti-ferromagnetic spin fluctuations dominating the normal state properties of electron-doped cuprates.

Development of nano- and microdevices for the next generation of biotechnology, wearables and miniaturized instrumentation

This is a short communication based on recent high-impact publications related to how various chemical materials and substrate modifications could be tuned for nano- and microdevices, where their application for high point-of-care bioanalysis and further applications in life science is discussed. Hence, they have allowed different high-impact research topics in a variety of fields, from the control of nanoscale to functional microarchitectures embedded in various support materials to obtain a device for a given application or use. Thus, their incorporation in standard instrumentation is shown, as well as in new optical setups to record different classical and non-classical light, signaling, and energy modes at a variety of wavelengths and energy levels. Moreover, the development of miniaturized instrumentation was also contemplated. In order to develop these different levels of technology, the chemistry, physics and engineering of materials were discussed. In this manner, a number of subjects that allowed the design and manufacture of devices could be found. The following could be mentioned by way of example: (i) nanophotonics; (ii) design, synthesis and tuning of advanced nanomaterials; (iii) classical and non-classical light generation within the near field; (iv) microfluidics and nanofluidics; (v) signal waveguiding; (vi) quantum-, nano- and microcircuits; (vii) materials for nano- and microplatforms, and support substrates and their respective modifications for targeted functionalities. Moreover, nano-optics in in-flow devices and chips for biosensing were discussed, and perspectives on biosensing and single molecule detection (SMD) applications. In this perspective, new insights about precision nanomedicine based on genomics and drug delivery systems were obtained, incorporating new advanced diagnosis methods based on lab-on-particles, labs-on-a-chip, gene therapies, implantable devices, portable miniaturized instrumentation, single molecule detection for biophotonics, and neurophotonics. In this manner, this communication intends to highlight recent reports and developments of nano- and microdevices and further approaches towards the incorporation of developments in nanophotonics and biophotonics in the design of new materials based on different strategies and enhanced techniques and methods. Recent proofs of concept are discussed that could allow new substrates for device manufacturing. Thus, physical phenomena and materials chemistry with accurate control within the nanoscale were introduced into the discussion. In this manner, new potential sources of ideas and strategies for the next generation of technology in many research and development fields are showcased.

This is a short communication based on recent high-impact publications related to how various chemical materials and substrate modifications could be tuned for nano- and microdevices, where their application for high point-of-care bioanalysis and further applications in life science is discussed.

High-T c Cuprates: a Story of Two Electronic Subsystems

A review of the phenomenology and microscopy of cuprate superconductors is presented, with particular attention to universal conductance features, which reveal the existence of two electronic subsystems. The overall electronic system consists of 1 + p charges, where p is the doping. At low dopings, exactly one hole is localized per planar copper-oxygen unit, while upon increasing doping and temperature, the hole is gradually delocalized and becomes itinerant. Remarkably, the itinerant holes exhibit identical Fermi liquid character across the cuprate phase diagram. This universality enables a simple count of carrier density and yields comprehensive understanding of the key features in the normal and superconducting state. A possible superconducting mechanism is presented, compatible with the key experimental facts. The base of this mechanism is the interaction of fast Fermi liquid carriers with localized holes. A change in the microscopic nature of chemical bonding in the copper oxide planes, from ionic to covalent, is invoked to explain the phase diagram of these fascinating compounds.