Spatial Wave Function Research Articles

Design of Three bit ADC and DAC Using Spatial Wave-function Switched SWSFETs

The spatial wave-function switched field effect transistor (SWSFET) has two or three low band-gap quantum well channels inside the substrate of the semiconductor. The applied voltage at the gate region of the SWSFET, switches the charge carrier concentration in different channels from the source to the drain region. The switching of the electron wave function in different channels can be explained by the device model of the SWSFET. A circuit model of a SWSFET is developed in the Berkeley Short Channel IGFET Model (BSIM) 4.0.0. The design of a three bit analog-to-digital converter (ADC) and digital-to-analog converter (DAC) using SWSFET is explained in this work. Advanced circuit design using fewer SWSFETs will reduce the device count in future analog and digital circuit design.

Dimensional Regularization of the Spatial wave function for a singular contact interaction in the Relativistic Schrodinger Equation

Based on our previous work in PRD 89, 125023 (2014), we stress here (for the first time) the regularization of the spatial wave function for the δ-contact interaction within the relativistic Schrodinger equation. The D-dimensional inverse Fourier transform has been utilized to map the momentum-space wave function to the spatial one. To regularize the logarithmic blow up of the wave function as x → 0, we employed the dimensional regularization technique. We assert that although the technique has been used here for the bound state only, the form of the scattering states in momentum space assures the reliability of the same technique to regularize the spatial scattering wave functions.

Inclusive production of J/ψandψ′ mesons at the LHC

We discuss the prompt production of $J/\psi$ mesons in proton-proton collisions at the LHC within a NRQCD $k_{t}$-factorization approach using Kimber-Martin-Ryskin (KMR) unintegrated gluon distributions (UGDF). We include both direct color-singlet production ($gg \to J/\psi$g) as well as a feed-down from $\chi_{c} \to J/\psi \gamma$ and $\psi' \to J/\psi X$. The production of the decaying mesons ($\chi_{c}$ or $\psi'$)is also calculated within NRQCD $k_{t}$-factorization. The corresponding matrix elements for $gg \to J/\psi$, $gg \to \psi'$ and $gg \to \chi_{c}$ include parameters of the nonrelativistic spatial wave functions of quarkonia at $r=0$, which are taken from potential models from the literature. We get the ratio of the corresponding of the cross sections for $\chi_{c}(2)$-to-$\chi_{c}(1)$ much closer to experimental data than obtained in recent analyses. Differential distributions in rapidity of $J/\psi$ and $\psi'$ are calculated and compared to experimental data of the ALICE and LHCb collaborations. We discuss possible onset of gluon saturation effects at forward/backward rapidities. One can describe the experimental data for $J/\psi$ production within model uncertainties with color-singlet component only. Therefore our theoretical results leave only a relatively small room for the color-octet contributions.

Antiferromagnetic Heisenberg Spin Chain of a Few Cold Atoms in a One-Dimensional Trap.

We report on the deterministic preparation of antiferromagnetic Heisenberg spin chains consisting of up to four fermionic atoms in a one-dimensional trap. These chains are stabilized by strong repulsive interactions between the two spin components without the need for an external periodic potential. We independently characterize the spin configuration of the chains by measuring the spin orientation of the outermost particle in the trap and by projecting the spatial wave function of one spin component on single-particle trap levels. Our results are in good agreement with a spin-chain model for fermionized particles and with numerically exact diagonalizations of the full few-fermion system.

Sum rules forspin−1/2quantum gases in states with well-defined spins. II. Spin-dependent two-body interactions

Sums of matrix elements of spin-dependent two-body momentum-independent interactions and sums of their products are calculated analytically in the basis of many-body states with given total spin --- the states built from spin and spatial wavefunctions belonging to multidimensional irreducible representations of the symmetric group, unless the total spin has the maximal allowed value. As in the first part of the series [V. A. Yurovsky, Phys. Rev. A 91, 053601 (2015)], the sum dependence on the many-body states is given by universal factors, which are independent of the Hamiltonians of non-interacting particles. The sum rules are applied to perturbative analysis of energy spectra and to calculation of two-body spin-dependent local correlations.

Logic Gates Design and Simulation Using Spatial Wavefunction Switched (SWS) FETs

This paper presents the design and modeling of logic gates using two channel spatial wavefunction switched field-effect transistors (SWSFETs) it is also known as a twin-drain MOSFET. In SWSFETs, the channel between source and drain has two or more quantum wells (QWs) layers separated by a high band gap material between them. The gate voltage controls the charge carrier concentration in the two quantum wells layers and it causes the switching of charge carriers from one channel to other channel of the device. The first part of this paper shows the characteristics of n-channel SWSFET model, the second part provides the circuit topology for the SWSFET inverter and universal gates- NAND, AND, NOR,OR, XOR and XOR. The proposed model is based on integration between Berkeley Short-channel IGFET Model (BSIM) and Analog Behavioral Model (ABM), the model is suitable to investigate the gates configuration and transient analysis at circuit level. The results show that all basic two-input logic gates can be implanted by using n-channel SWSFET only, It covers less area compared with CMOS (Complementary metal–oxide–semiconductor) gates. The NAND-NOR can be performed by three SWSFET, moreover the exclusive-NOR “XNOR” can be done by four SWSFET transistors also AND, OR, XOR gates require two additional SWSFET for inverting.

Sum rules for spin-1/2quantum gases in states with well-defined spins: Spin-independent interactions and spin-dependent external fields

Analytical expressions are derived for sums of matrix elements and their squared moduli over many-body states with given total spin --- the states built from spin and spatial wavefunctions belonging to multidimensional irreducible representations of the symmetric group, unless the total spin has the maximal allowed value. For spin-dependent one-body interactions with external fields and spin-independent two-body ones between the particles, the sum dependence on the many-body states is given by universal factors, which are independent of the interaction details and Hamiltonians of non-interacting particles. The sum rules are applied to perturbative analysis of energy spectra.

Unipolar Logic Gates Based on Spatial Wave-Function Switched FETs

The spatial wave-function switched field-effect transistor (SWSFET) has two or three low bandgap quantum well channels that can conduct carrier flow from source to drain of the SWSFET. Because of this property, SWSFETs are useful to implement different multivalued logic with reduced device count. In this paper, we introduce the circuit model of a SWSFET and the design of a unipolar inverter where only one kind of charge carrier contributes to the current flow. We also simulate two input unipolar logic gates such as NAND and NOR and demonstrate their universal property to implement other unipolar logic gates. We also simulate NOR gate and full adder circuits based on unipolar logic gates.

Newtonian self-gravitation in the neutral meson system

We derive the effect of the Schr\"odinger-Newton equation, which can be considered as a nonrelativistic limit of classical gravity, for a composite quantum system in the regime of high energies. Such meson-antimeson systems exhibit very unique properties, e.g., distinct masses due to strong and electroweak interactions. This raises an immediate question: what does one mean by mass in gravity for a state that is a superposition of mass eigenstates due to strong and electroweak interactions? We find conceptually different physical scenarios due to lacking of a clear physical guiding principle to explain which mass is the relevant one and due to the fact that it is not clear how the flavor wave function relates to the spatial wave function. There seems to be no principal contradiction. However, a nonlinear extension of the Schr\"odinger equation in this manner strongly depends on the relation between the flavor wave function and spatial wave function and its particular shape. In opposition to the continuous spontaneous localization collapse models we find a change in the oscillating behavior and not in the damping of the flavor oscillation.

Compressive direct measurement of the quantum wave function.

The direct measurement of a complex wave function has been recently realized by using weak values. In this Letter, we introduce a method that exploits sparsity for the compressive measurement of the transverse spatial wave function of photons. The procedure involves weak measurements of random projection operators in the spatial domain followed by postselection in the momentum basis. Using this method, we experimentally measure a 192-dimensional state with a fidelity of 90% using only 25 percent of the total required measurements. Furthermore, we demonstrate the measurement of a 19,200-dimensional state, a task that would require an unfeasibly large acquiring time with the standard direct measurement technique.

Toward ultimate nanoplasmonics modeling.

Advances in the field of nanoplasmonics are hindered by the limited capabilities of simulation tools in dealing with realistic systems comprising regions that extend over many light wavelengths. We show that the optical response of unprecedentedly large systems can be accurately calculated by using a combination of surface integral equation (SIE) method of moments (MoM) formulation and an expansion of the electromagnetic fields in a suitable set of spatial wave functions via fast multipole methods. We start with a critical review of volume versus surface integral methods, followed by a short tutorial on the key features that render plasmons useful for sensing (field enhancement and confinement). We then use the SIE-MoM to examine the plasmonic and sensing capabilities of various systems with increasing degrees of complexity, including both individual and interacting gold nanorods and nanostars, as well as large random and periodic arrangements of ∼1000 gold nanorods. We believe that the present results and methodology raise the standard of numerical electromagnetic simulations in the field of nanoplasmonics to a new level, which can be beneficial for the design of advanced nanophotonic devices and optical sensing structures.

Entanglement Entropies in the Ground States of Helium-Like Atoms

We examine the entanglement in the ground states of helium and helium-like ions using an original Hylleraas expansion. The von Neumann and linear entropies of the reduced density matrix are accurately computed by performing the Schmidt decomposition of the S singlet spatial wavefunctions. The results presented are more accurate than currently available in published literature.

Design of four-state inverter based on spatial wave-function switched FETs

A spatial wave-function switched field effect transistor (SWSFET) conducts current from the source to the drain region through different channels inside the FET based on the applied gate voltage. A circuit model of SWSFET is developed by modifying Berkeley short-channel IGFET model (BSIM 3.2.0), and a four-state inverter is designed based on that model. This four-state inverter may become a key element in future quaternary logic circuit design.

Implementation of Membership Function using Spatial Wave-Function Switched FETs

Spatial wave-function switched field effect transistor (SWSFET) switches the current flow between different channels inside the FET based on the applied voltage in its gate terminal. SWSFET can be used to implement multi-valued logic circuit with less number of circuit elements. Recently we presented unipolar inverter circuit using SWSFET. In this paper we develop a circuit model of SWSFET based on BSIM 3.2.0 and BSIM 3.2.4 and implement membership function using that circuit model of SWSFET. The spatial wave-function switched field effect transistor (SWSFET) has two or three low band-gap quantum well channels inside the substrate of the semiconductor. Applied voltage at the gate region of the SWSFET, switches the charge carrier concentration in different channels from source to drain region. A circuit model of SWSFET is developed in BSIM 3.2.0. Membership function is implemented using the circuit model of the SWSFET. Membership function implementation using less number of SWSFET will reduce the device count in future analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuits.

Color spin wave functions of heavy tetraquark states

Using the variational method, we calculate the mass of the J^P=1^+ (ud)bar(bb) tetraquark containing two identical heavy antiquarks in a nonrelativistic potential model with color confinement and spin hyperfine interaction. In particular, we extend a previous investigation of the model by Brink and Stancu by investigating the effect of including the color anti-sextet component of the diquark configuration as well as using several more Gaussian parametrization for the L=0 part of the spatial wave function. We find that for the heavy tetraquark, the 6bar{6} component among the color singlet bases is negligible and that the previously used specific Gaussian spatial configuration is good enough in obtaining the ground state energy.

Unified dynamics of electrons and photons viaZitterbewegungand spin-orbit interaction

We show that when an electron or photon propagates in a cylindrically symmetric waveguide, it experiences both a zitterbewegung effect and a spin-orbit interaction leading to identical propagation dynamics for both particles. Applying a unified perturbative approach to both particles simultaneously, we find that to first-order in perturbation theory their Hamiltonians each contain identical Darwin (zitterbewegung) and spin-orbit terms, resulting in the unification of their dynamics. The presence of the zitterbewegung effect may be interpreted physically as the delocalization of the electron on the scale of its Compton wavelength, or the delocalization of the photon on the scale of its wavelength in the waveguide. The presence of the spin-orbit interaction leads to the prediction of several rotational effects: the spatial or time evolution of either particle's spin/polarization vector is controlled by the sign of its orbital angular momentum quantum number, or conversely, its spatial wave function is controlled by its spin angular momentum.

Imaging of spatial many-body wave functions via linear momentum measurements

The equivalence of a complete characterization of linear momenta of fragments from a many-body fragmentation process and the spatial wave function of the many-body system is discussed. Our experiment on three-body dissociation of state selected H3 and D3 molecules into ground-state hydrogen atoms strongly suggests the existence of such a close relationship as it is also predicted by theory in the form of the imaging theorem. We conclude that prudent imaging of many-body fragmentation provides a laboratory view of the squared many-body wave function at a spatial scale of molecular dimensions at which fragments exit into the realm of independent free particles.

Independent bases on the spatial wavefunction of four-identical-particle systems

We construct the independent bases on the spatial wavefunction of four-identical-particle systems classified under the rotational group SO(3) and the permutation group S4 with the usage of transformation coefficients that relate wavefunctions described in one set of internal coordinates with those in another. The basis functions for N ⩽ 2 are presented in the explicit expressions based on the harmonic oscillator model. Such independent bases are supposed to play a key role in the construction of the wavefunctions of the five-quark states and the variation calculation of four-body systems. Our prescription avoids the spurious states and can be programmed for arbitrary N.

Ge-ZnSSe Spatial Wavefunction Switched (SWS) FETs to Implement Multibit SRAMs and Novel Quaternary Logic

This paper describes novel multibit static random-access memories (SRAMs) implemented using four-channel spatial wavefunction switched field-effect transistors (SWS FETs) with Ge quantum wells and ZnSSe barriers. A two-bit SRAM cell consists of two back-to-back connected four-channel SWS FETs, where each SWS FET serves as a quaternary inverter. This architecture results in a reduction of the field-effect transistor (FET) count by 75% and data interconnect density by 50%. The designed two-bit SRAM cell is simulated using Berkeley short-channel insulated-gate field-effect transistor equivalent-channel models (for 25-nm FETs). In addition, the binary interface logic and conversion circuitry are designed to integrate the SWS SRAM technology. Our motivation is to stack up multiple bits on a single SRAM cell without multiplying the transistor count. The concept of spatial wavefunction switching (SWS) in the FET structure has been verified experimentally for two- and four-well structures. Quantum simulations exhibiting SWS in four-well Ge SWS FET structures, using the ZnSe/ZnS/ZnMgS/ZnSe gate insulator, are presented. These structures offer higher contrast than Si-SiGe SWS FETs.

Four-State Sub-12-nm FETs Employing Lattice-Matched II–VI Barrier Layers

Three-state behavior has been demonstrated in Si and InGaAs field-effect transistors (FETs) when two layers of cladded quantum dots (QDs), such as SiOx-cladded Si or GeOx-cladded Ge, are assembled on the thin tunnel gate insulator. This paper describes FET structures that have the potential to exhibit four states. These structures include: (1) quantum dot gate (QDG) FETs with dissimilar dot layers, (2) quantum dot channel (QDC) with and without QDG layers, (3) spatial wavefunction switched (SWS) FETs with multiple coupled quantum well channels, and (4) hybrid SWS–QDC structures having multiple drains/sources. Four-state FETs enable compact low-power novel multivalued logic and two-bit memory architectures. Furthermore, we show that the performance of these FETs can be enhanced by the incorporation of II–VI nearly lattice-matched layers in place of gate oxides and quantum well/dot barriers or claddings. Lattice-matched high-energy gap layers cause reduction in interface state density and control of threshold voltage variability, while providing a higher dielectric constant than SiO2. Simulations involving self-consistent solutions of the Poisson and Schrodinger equations, and transfer probability rate from channel (well or dot layer) to gate (QD layer) are used to design sub-12-nm FETs, which will aid the design of multibit logic and memory cells.