Quantum Mechanical Phenomena Research Articles

The method of single expression (MSE) as a prospective modeling tool for boundary value problems: an extension from nano-optics to quantum mechanics

Mathematical description of the wave phenomena in nano-optics and quantum mechanics is similar and requires wavelength-scale analysis of wave interaction with nano-layers in optics and micro-particle interaction with potential barriers or wells in quantum mechanics. Traditionally, when dealing with boundary problems in nano-optics and quantum mechanics, the same fundamental approach of counter-propagating waves is often being used, when general solutions of the wave equations are presented as a sum of counter-propagating waves. This type of solution presentation relies on the superposition principle restricting correct description of strong intensity-dependent nonlinear wave-matter interaction. The non-traditional method of single expression (MSE) does not exploit the superposition principle, but rather uses resulting field representation and backward-propagation algorithm allowing to obtain correct steady-state solutions of boundary value problems without approximations and at any value of wave intensity by taking into account correctly intensity-dependent nonlinearity, loss or gain in a medium. In the present work a detailed description of the MSE approach extended for one dimensional quantum mechanical boundary value problems is presented. Results of numerical simulations by the MSE of electron tunneling through rectangular single and double potential barriers are presented and discussed.

Gold Nanoparticles on TM:ZnO (TM: Fe, Co) as Spinplasmon-Assisted Electro-Optic Reaction Modulator in Solar-to-Hydrogen Water Splitting Cell

The optical spintronic injection is a perspective issue about spintronics in semiconductors. Here, we report the simultaneous operation and effective control of the spincurrent from nanostructures in a semiconductor by combining the spin of a photoelectron for hydrogen production. The surface plasmon resonance (SPR) of gold-coated Fe:ZnO or Co:ZnO NRs (nanorods) is excited by the circular polarization light of coherent ℏ/–ℏ injection. The efficiency of spintronic-photoelectrochemical (SPEC) hydrogen production of Au/Fe:ZnO NRs irradiated by coherent ℏ/–ℏ circular polarization is as high as 188.76%, about 5 times higher than pure ZnO NRs. In the study, the system with two qubits can be in any superposition to four different bits, which utilizes quantum mechanical phenomena to improve SPEC hydrogen production efficiency. The injection of optical spintronics is significantly tuned for the environmentally friendly applications as the development of alternative energy.

OTHER MATTERS

Karen Barad’s Meeting the Universe Halfway relies on mutually incompatible grounding gestures, one of which describes the relationality of an always already material-discursive reality, while the other seeks to ground this relation one-sidedly in matter. These two materialisms derive from the gesture she borrows from the New Materialist (and other related) fields, which posits her work as an advance over the history of “representationalism” and “social constructivism.” In turn, this one-sided materialism produces a skewed reading of the quantum mechanical phenomena with which she engages. Her attempt to create an ontological (not epistemological) interpretation of quantum mechanics proves deconstructible. Instead, a science of undecidability or science of quant à helps us to understand debates among scientists and philosophers over the completeness or incompleteness of quantum mechanics and its epistemological or ontological status – by demonstrating that these questions will necessarily remain unresolved.

SCIENCE FICTION AND METHODOLOGY

SCIENCE FICTION AND METHODOLOGY

What is Quantum Computing and How it Works, Artificial Intelligence Driven by Quantum Computing

Quantum Computing (QC) is designed and structured around the usage of Quantum Mechanical (QM) concepts and phenomena...

Symmetry and Signs of Self-Organized Criticality in Living Organisms

Symmetry methods have been of crucial importance to physics. Group theory and conservation laws have become the fundamental language of symmetries, going all the way from the realm of quantum mechanical phenomena to general relativity. However, these ideas have had less impact in the biological domain. In this paper we present a view of self-organized biological systems as characterized by and evolving towards critical points, in the language of phase transitions as seen in physical systems. Self-similar (or scale invariant) behavior seems to signal homeostatic dynamical equilibrium in living organisms. Deviations of this homeostatic balance is associated with illness and elderly.

A gravitational collapse singularity theorem consistent with black hole evaporation

The global hyperbolicity assumption present in gravitational collapse singularity theorems is in tension with the quantum mechanical phenomenon of black hole evaporation. In this work I show that the causality conditions in Penrose's theorem can be almost completely removed. As a result, it is possible to infer the formation of spacetime singularities even in the absence of predictability and hence compatibly with quantum field theory and black hole evaporation.

Spontaneous symmetry breaking in purely nonlinear fractional systems.

Spontaneous symmetry breaking, a spontaneous course of breaking the spatial symmetry (parity) of the system, is known to exist in many branches of physics, including condensed-matter physics, high-energy physics, nonlinear optics, and Bose-Einstein condensates. In recent years, the spontaneous symmetry breaking of solitons in nonlinear wave systems is broadly studied; understanding such a phenomenon in nonlinear fractional quantum mechanics with space fractional derivatives (the purely nonlinear fractional systems whose fundamental properties are governed by a nonlinear fractional Schrödinger equation), however, remains pending. Here, we survey symmetry breaking of solitons in fractional systems (with the fractional diffraction order being formulated by the Lévy index α) of a nonlinear double-well structure and find several kinds of soliton families in the forms of symmetric and anti-symmetric soliton states as well as asymmetric states. Linear stability and dynamical properties of these soliton states are explored relying on linear-stability analysis and direct perturbed simulations, with which the existence and stability regions of all the soliton families in the respective physical parameter space are identified.

Testing of code-based pseudorandom number generators for post-quantum application

Recent advances in quantum computing based on new principles and phenomena of quantum mechanics show that quantum cryptanalysis of modern cryptographic algorithms can become real in the coming years. For example, according to the forecasts of the US National Institute of Standards and Technology (NIST) in the next decade, quantum cryptanalysis of most asymmetric cryptosystems used today will be available. For this reason, NIST announced a contest of post-quantum (i.e., resistant to quantum cryptanalysis) cryptographic algorithms for directional encryption, electronic signature, and key encapsulation. In the coming years, standardization of the selected algorithms and their early implementation is expected. Obviously, other cryptographic algorithms, for example, pseudorandom number generators based on solving complex theoretical problems (discrete logarithm, factorization, etc.), will also be subject to further revision. These generators must also be replaced by reliable and safe algorithms suitable for use even in the conditions of the possible application of quantum cryptanalysis (i.e., in the post-quantum period). This paper is devoted to the study of provably secure generators whose resistance is based on the complexity of solving the syndrome decoding problem. This structure allows the generators to keep the resistance to both classical cryptanalysis and cryptanalysis using quantum computing. The design features of classic code-based generator representative proposed by Fisher and Stern are presented, and a new generator scheme is proposed to overcome the drawback of its predecessor, such as a reduced practical maximum period length, by using a linear feedback shift register. Within this paper Results of heuristic testing of the above-mentioned generators is conducted in terms of the sequence period, the speed of sequence generation, the cryptographic resistance of the generators and the possibility of their use in the post-quantum period.

A Generalized Quantum Algorithm for Assuring Fairness in Random Selection Among 2N Participants

Quantum computing promises to provide a tremendous boost to the computational power of our machines by utilizing superposition and entanglement phenomenon of quantum mechanics. Few quantum algorithms are known which are taking advantage of these quantum phenomena and are providing solutions to problems having significant importance. In this paper, we have proposed a generalized method for designing 2N qubits circuit such that during measurement only one qubit will be in state-1, while remaining other qubits will hold state-0. Apart from adding fair randomness to the selection process in distributed quantum computing, these generalized quantum circuits can be found very useful in commercial domains requiring transparency and trust in systems requiring fair randomness in decision-making such as in a lottery system. The critical advantage of using our proposed method is that it allows individual’s results to be teleported to them, hence making an end-to-end system whose fairness is quantum assured.

Improved Ternary Reversible Logic Synthesis Using Group Theoretic Approach

Quantum computation relies on exploiting quantum mechanical phenomena, and has received significant attention in recent years. Higher-dimensional quantum systems increase the density of encoded information per computing element (e.g., qutrit for three-level system), resulting in less resource overhead. For instance, 63% reduction in the number of qutrits is possible for ternary quantum systems as compared to the corresponding binary systems. The proposed work exploits this fact to synthesize ternary reversible circuits employing a cycle-based technique. The method starts from the ternary reversible specification of a given function in the form of a permutation. The permutation cycles are factored into simpler three-cycles and two-cycles, which are then mapped to ternary reversible gates. Different gate libraries are used to synthesize three-cycles and two-cycles, respectively. A gate decomposition approach is also proposed to synthesize a quantum gate netlist in terms of elementary ternary quantum gates, viz. Muthukrishnan–Stroud gate and shift gate. Synthesis results on benchmark functions indicate that the proposed method results in 27% and 6% improvements in quantum cost and gate count, respectively, over existing works in the literature.

Rogue Wave Solutions and Modulation Instability With Variable Coefficient and Harmonic Potential

The article studies the propagation of rogue waves with a nonautonomous NLSE in presence of external potential, which is considered as an important model for many physical phenomena in quantum mechanics. The obtained waves are of first and second-order, and are investigated using similarity transformation. The nonlinear dynamical behaviour of these waves has also been demonstrated in the presence of gravity and magnetic fields. The result shows the influence of gravity and magnetic fields over density, width and peak heights. Moreover, the modulation instability has also been discussed.

Structure, magnetic and dielectric properties in nano-crystalline Yb[formula omitted]CoMnO[formula omitted

Structural, magnetic and dielectric properties have been studied for Yb2CoMnO6. Nano-crystalline sample of Yb2CoMnO6 synthesized by sol–gel method and structural analysis shows that the sample crystallizes in monoclinic crystal structure with P21/n phase group. To understand the charge state of Co, Mn and Yb we have performed the XPS study. Magnetic study shows that the sample undergoes a paramagnetic to ferromagnetic phase transition around Tc∼56 K and an additional magnetic ordering at a lower temperature around 14 K due to ordering of Yb3+ magnetic ions. Temperature dependent Raman study reveals that spin–phonon interaction is present in this material. Further, we have studied the dielectric properties of this material. We observed that the material shows a relaxation behavior that obeys the thermally activated relaxation mechanism. Impedance spectroscopy reveals that the material shows non-Debye’s behavior. AC conductivity study is performed to understand the conduction mechanics which involve the quantum mechanical tunneling phenomenon.

DFT and MD simulation supplemented experiments for isotopic fractionation of zinc compounds using a macrocyclic crown ether appended polymeric resin.

Isotope effect is a quantum mechanical phenomenon and thus poses a challenge for the separation of isotopes of an element of interest, especially for heavy elements. Isotopic fractionation of zinc is also quite difficult and challenging but is necessitated due to various applications of its isotopes ranging from nuclear medicine to nuclear power reactors. Here, we developed the dibenzo-18-crown-6 (DB18C6) ether-functionalized poly(methacrylic acid) (PMA) resin by exploiting the ion and isotope recognition ability of the crown ether using DFT/MD simulations followed by experiments for isotopic fractionation of zinc. The PMADB18C6 adsorbent was prepared and suitably characterized. Both computational and experimental findings demonstrate that the adsorption and isotope separation of zinc with PMADB18C6 are due to the molecular recognition effect of the "O" dipole of the crown ether. Furthermore, both MD simulations and experiments suggest Langmuir type adsorption isotherms. The adsorption of Zn2+ ions on the PMA resin is predicted to be endothermic, whereas it is exothermic on the PMADB18C6 resin, as revealed from the experimentally observed enthalpy change. A small scale fixed bed column study was demonstrated to test the scale-up application. The values of the experimental separation factors: 1.0013 for 66/64 and 1.0027 for 68/64 confirm the computationally predicted results of 1.00088 and 1.0010, respectively, thus establishing the combined strength of the theory and experiments for the identification of efficient fractionating agents for a complex quantum isotope effect which eventually helps in planning further experiments in view of medicinal and technological applications of zinc isotopes.

Quantum effects in complex systems: summarizing remarks.

Quantum mechanical phenomena such as coherence, spin dynamics, and tunneling have been observed in biological, electrochemical, polymeric, and many other condensed phase processes. This paper summarizes the diverse contributions to the Faraday Discussion on quantum effects in complex systems. Various processes exhibiting quantum mechanical behavior were examined using advanced spectroscopic and theoretical methods. An emerging theme was the critical importance of feedback between experiment and theory, particularly in the form of experimental testing of theoretical predictions.

Performance of New Hope and CRYSTALS-Dilithium Postquantum Schemes in the Transport Layer Security Protocol

In recent years, there has been a notable amount of research on developing cryptographic schemes that are secure against both quantum and classical computers. In 2016, the National Institute of Standards and Technology (NIST) initiated a process to solicit, evaluate, and standardize one or more quantum-resistant public key cryptographic schemes. This process originated because quantum computers can exploit quantum mechanical phenomena and solve mathematical problems that are difficult or intractable for classical computers. This kind of mathematical problem is the basis of secure public key cryptography. As a consequence, in a near future quantum computers will be able to break many of the public key schemes currently in use. However, the challenge is especially acute for devices with different architectures. They might not be well equipped to run the new standards and interoperate with existing communication protocols and networks. In this work, we analyze the performance of postquantum schemes in the transport layer security (TLS) protocol considering x86 as the server architecture and x86/ARM architectures as clients. All of them lack cloud computing or virtualized environments. Our analysis considers integrating the implementation of two cryptographic schemes that were successful in the second round of the postquantum standardization process, namely, Dilithium and New Hope. The performance of postquantum schemes in the TLS protocol is statistically analyzed in x86 and ARM architectures, giving the relationships, the effects and the survival of the analysis.

Quenched tunneling in ammonia

Quantum Mechanics Inversion between two energetically equivalent umbrella-spaced configurations in ammonia (NH3) is a classic textbook example of tunneling in a symmetric double-minimum potential. Park et al. report on how a very strong direct-current electric field, as powerful as intermolecular interactions, can suppress this quantum mechanical phenomenon in the system. They observed that NH3 molecules isolated in a solid argon matrix at 10 kelvin strongly orient along the external field direction and that, as the field is increased up to 200 million volts per meter, their energy states shift, eventually quenching the tunneling from the normal state to the inverted one. The observed changes are reversible and open up opportunities for manipulating tunneling dynamics in many other molecules. Proc. Natl. Acad. Sci. U.S.A. 116 , 23444 (2019).

State-independent contextuality in classical light

State-independent contextuality is a fundamental phenomenon in quantum mechanics, which has been demonstrated experimentally in different systems in recent years. Here we show that such contextuality can also be simulated in classical optical systems. Using path and polarization degrees of freedom of classical optics fields, we have constructed the classical trit (cetrit), here the term ‘cetrit’ is the classical counterpart of a qutrit in quantum systems. Furthermore, in classical optical systems we have simulated the violations of several Yu-Oh-like noncontextual inequalities in a state-independent manner by implementing the projection measurements. Our results not only provide new physical insights into the contextuality and also show the application prospects of the concepts developed recently in quantum information science to classical optical systems and optical information processes.

Chiral Induction on the Ultrafast Event of Excited State Proton Transfer Can Probe Its Mechanism

AbstractWhen protonic motion is explained as a purely quantum mechanical phenomenon, two extreme situations can be visualized as either the adiabatic or the nonadiabatic limit of proton transfer (PT). Strong orbital coupling between the donor and the acceptor pair in the proton transfer step drives PT mechanism in the adiabatic limit whereas in nonadiabatic limit PT predominantly occurs through tunneling. Here we proposed a unique way to experimentally observe the adiabaticity of PT by introducing chirality in the reaction coordinate of excited state proton transfer (ESPT). We successfully established the existence of prominent role of diastereomerism in the ESPT by both steady state and femtosecond time‐resolved transient absorption spectroscopic measurements in the adiabatic limit. The presented novel approach can overcome the limitations of only available experimental technique, i. e. kinetic isotope effect, to elucidate proton transfer mechanism.

Quantum tunnelling, real-time dynamics and Picard-Lefschetz thimbles

We follow up the work, where in light of the Picard-Lefschetz thimble approach, we split up the real-time path integral into two parts: the initial density matrix part which can be represented via an ensemble of initial conditions, and the dynamic part of the path integral which corresponds to the integration over field variables at all later times. This turns the path integral into a two-stage problem where, for each initial condition, there exits one and only one critical point and hence a single thimble in the complex space, whose existence and uniqueness are guaranteed by the characteristics of the initial value problem. In this paper, we test the method for a fully quantum mechanical phenomenon, quantum tunnelling in quantum mechanics. We compare the method to solving the Schrödinger equation numerically, and to the classical-statistical approximation, which emerges naturally in a well-defined limit. We find that the Picard-Lefschetz result matches the expectation from quantum mechanics and that, for this application, the classical-statistical approximation does not.