Adiabatic quantum algorithm for factorization with growing minimum energy gap

2021 ◽  
Author(s):  
Bao Yan ◽  
Haocong Jiang ◽  
Ming Gao ◽  
Qianheng Duan ◽  
Hong Wang ◽  
...  
Keyword(s):  
Energy Gap ◽  
Minimum Energy ◽  
Quantum Algorithm

scholarly journals A NOVEL FRACTAL GEOMETRY DOPING FOR GRAPHENE NANORIBBON AND THE OPTIMIZATION OF CRYSTAL: A DENSITY FUNCTIONAL THEORY (DFT) STUDY

2020 ◽  
Vol 17 (35) ◽  
pp. 1148-1158
Author(s):  
Mohammed L. JABBAR ◽  
Kadhum J. AL-SHEJAIRY
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Minimum Energy ◽  
Graphene Nanoribbon ◽  
Chemical Doping ◽  
Functional Theory ◽  
Lower Reactivity ◽  
The Density Functional Theory ◽  
Semiconductor Behavior

Chemical doping is a promising route to engineering and controlling the electronic properties of the zigzag graphene nanoribbon (ZGNR). By using the first-principles of the density functional theory (DFT) calculations at the B3LYP/ 6-31G, which implemented in the Gaussian 09 software, various properties, such as the geometrical structure, DOS, HOMO, LUMO infrared spectra, and energy gap of the ZGNR, were investigated with various sites and concentrations of the phosphorus (P). It was observed that the ZGNR could be converted from linear to fractal dimension by using phosphorus (P) impurities. Also, the fractal binary tree of the ZGNR and P-ZGNR structures is a highlight. The results demonstrated that the energy gap has different values, which located at this range from 0.51eV to 1.158 eV for pristine ZGNR and P-ZGNR structures. This range of energy gap is variable according to the use of GNRs in any apparatus. Then, the P-ZGNR has semiconductor behavior. Moreover, there are no imaginary wavenumbers on the evaluated vibrational spectrum confirms that the model corresponds to minimum energy. Then, these results make P-ZGNR can be utilized in various applications due to this structure became more stable and lower reactivity.

scholarly journals DFT calculations as an efficient tool for prediction of Raman and infra-red spectra and activities of newly synthesized cathinones

2020 ◽  
Vol 18 (1) ◽  
pp. 185-195
Author(s):  
Maja Vujović ◽  
Venkatesan Ragavendran ◽  
Biljana Arsić ◽  
Emilija Kostić ◽  
Milan Mladenović
Keyword(s):  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Minimum Energy ◽  
Density Functional Theory Calculations ◽  
Maximum Energy ◽  
Monoamine Transporters ◽  
Good Tool ◽  
Molecular Orbital Analysis ◽  
Experimental Values

AbstractInitially made for medical treatment for Parkinsonism, obesity, and depression, cathinones have become illegal drugs for the “recreational use”. The mechanism of action of synthetic cathinones consists of the inhibition of monoamine transporters. DFT (Density Functional Theory) calculations on the selected cathinones (3-FMC, 4-FMC, 4-MMC, Buphedrone, Butylone, Ethylone, MDPV, Methcathinone, and Methylone) were performed using B3LYP level of the Gaussian 09 program suite. The unscaled B3LYP/6–31G vibrational wavenumbers are in general larger than the experimental values, so the use of selective scaling was necessary. The calculated spectra of selected cathinones are in good correlation with the experimental spectra which demonstrates that DFT is a good tool for the prediction of spectra of newly synthesized and insufficiently experimentally characterised cathinones. Also, HOMO-LUMO (Highest Occupied Molecular Orbital-Lowest Unoccupied Molecular Orbital) analysis shows that 3-FMC possesses the minimum energy gap of 3.386 eV, and the molecule 4-FMC possesses the maximum energy gap of 4.205 eV among the investigated cathinones. It indicates that 3-FMC would be highly reactive among all the cathinones under investigation.

scholarly journals The role of symmetries in adiabatic quantum algorithms

2010 ◽  
Vol 10 (1&2) ◽  
pp. 109-140
Author(s):  
G. Schaller ◽  
R. Schutzhold
Keyword(s):  
Energy Gap ◽  
Quantum Phase Transitions ◽  
Quantum Algorithms ◽  
Quantum Algorithm ◽  
First Order ◽  
Pauli Matrices ◽  
Np Problems ◽  
Search Routine ◽  
Better Than

Exploiting the similarity between adiabatic quantum algorithms and quantum phase transitions, we argue that second-order transitions -- typically associated with broken or restored symmetries -- should be advantageous in comparison to first-order transitions. Guided by simple examples we construct an alternative adiabatic algorithm for the NP-complete problem {\em Exact Cover 3}. We show numerically that its average performance (for the considered cases up to $\ord\{20\}$ qubits) is better than that of the conventional scheme. The run-time of adiabatic algorithms is not just determined by the minimum value of the fundamental energy gap (between the ground state and the exited states), but also by its curvature at the critical point. The proposed symmetry-restoring adiabatic quantum algorithm only contains contributions linear and quadratic in the Pauli matrices and can be generalized to other problem Hamiltonians which are decomposed of terms involving one and two qubits. We show how the factoring problem can be cast into such a quadratic form. These findings suggest that adiabatic quantum algorithms can solve a large class of NP problems much faster than the Grover search routine (which corresponds to a first-order transition and yields a quadratic enhancement only).

Network-Pharmacology and DFT Based Approach Towards Identification of Leads from Homalomena aromatica for Multi-Target In-Silico Screening on Entamoeba histolytica Proteins

2020 ◽  
Vol 15 (3) ◽  
pp. 226-237 ◽  
Author(s):  
Ashis Kumar Goswami ◽  
Hemanta Kumar Sharma ◽  
Neelutpal Gogoi ◽  
Bhaskar Jyoti Gogoi
Keyword(s):  
Entamoeba Histolytica ◽  
Density Functional ◽  
Energy Gap ◽  
Intestinal Parasites ◽  
Minimum Energy ◽  
Docking Studies ◽  
Network Pharmacology ◽  
Cysteine Synthase ◽  
Discovery Studio ◽  
Amoebic Dysentery

Background: Entamoeba histolytica is the primary protozoan that causes amoebic dysentery and is prioritized as the third most prevalent protozoan causing parasitosis. Drug of choice in amoebic dysentery is metronidazole but it has unpleasant side effects with reports of development of resistance in certain cases. Homalomena aromatica Schott. is a plant which is used in different ethnomedicinal practices of South-east Asia to treat stomach ailments against intestinal parasites. Objective: the present study, a docking weighted network pharmacology-based approach was employed to understand the effects of a library of 71 natural molecules reported from Homalomena aromatica with reference to four proteins of Entamoeba histolytica namely thioredoxin reductase, cysteine synthase, glyceraldehyde-3-phosphate dehydrogenase, and ornithine decarboxylase. Method: Molecular docking of the phytoconstituents of H. aromatica was performed in Biovia Discovery Studio 2017 R2 software suite on the selected proteins of E. histolytica. A connection was established between the proteins and molecules through network pharmacology weighted docking studies with the help of Cytoscape V3.4.0 software to select three molecules namely HM 7, HM 23 and HM 24 on the basis of the generated network between the molecules and targets. Quantum mechanics based Density Functional Theory (DFT) analysis was performed on the filtered molecules to ascertain their viability with respect to LUMO-HOMO orbital energies of the filtered molecules. Results: On the basis of the docking studies of the natural molecules on the selected protein targets, a network of molecules was built. DFT based minimum energy gap was analysed to further ascertain the most potential inhbitors. Three molecules from H. aromatica; 3,7-dimethylocta-1,6-dien-3- yl acetate, α -methyl-α-(4-methyl-3-pentenyl)-oriranemethanol, and 7-octadiene-2,6-diol-2,6- dimethyl were predicted to be potential lead molecules against amoebiasis. Conclusion: The present study provides important evidence for the development of new drug molecules to treat amoebiasis.

Design of HP Models of Proteins by Energy Gap Criterion Using Continuous Modeling and Optimization

2004 ◽  
Author(s):  
Sung K. Koh ◽  
G. K. Ananthasuresh
Keyword(s):  
Protein Design ◽  
Compliant Mechanisms ◽  
Energy Gap ◽  
Minimum Energy ◽  
Continuous Optimization ◽  
Combinatorial Problem ◽  
Energy Criterion ◽  
Optimization Method ◽  
Protein Chain ◽  
Folded Structure

The sequence of 20 types of amino acid residues in a heteropolymer chain of a protein is believed to be the basis for the 3-D conformation (folded structure) that a protein assumes to serve its functions. We present a deterministic optimization method to design the sequence of a simplified model of proteins for a desired conformation. A design methodology developed for the topology optimization of compliant mechanisms is adapted here by converting the discrete combinatorial problem of protein sequence design to a continuous optimization problem. It builds upon our recent work which used a minimum energy criterion on a deterministic approach to protein design using continuous models. This paper focuses on the energy gap criterion, which is argued to be one of the most important characteristics determining the stable folding of a protein chain. The concepts, methodology, and illustrative examples are presented using HP models of proteins where only two types (H: hydrophobic and P: polar) of monomers are considered instead of 20. The highlight of the method presented in this paper is the drastic reduction in computational costs.

scholarly journals Speedup in Quantum Adiabatic Evolution Algorithm

2003 ◽  
Vol 58 (4) ◽  
pp. 201-203 ◽  
Author(s):  
Joonwoo Bae ◽  
Younghun Kwon
Keyword(s):  
Energy Gap ◽  
Minimum Energy ◽  
Ground Level ◽  
Point Of View ◽  
Adiabatic Evolution ◽  
Exact Relation ◽  
Adiabatic Theorem ◽  
Running Time ◽  
Evolution Algorithm ◽  
Quantum Adiabatic Evolution

The quantum adiabatic evolution algorithm suggested by Farhi et al. was effective in solving NPcomplete problems. The algorithm is governed by the adiabatic theorem. Therefore, in order to reduce the running time, it is essential to examine the minimum energy gap between the ground level and the next one in the evolution. In this paper we show a way of speedup in the quantum adiabatic evolution algorithm, using an extended Hamiltonian. We present the exact relation between the energy gap and the elements of the extended Hamiltonian, which provides a new point of view to reduce the running time.

scholarly journals Stabilizers as a design tool for new forms of the Lechner-Hauke-Zoller annealer

2016 ◽  
Vol 2 (10) ◽  
pp. e1601246 ◽  
Author(s):  
Andrea Rocchetto ◽  
Simon C. Benjamin ◽  
Ying Li
Keyword(s):  
Energy Gap ◽  
Minimum Energy ◽  
Annealing Process ◽  
Triangular Array ◽  
Design Tool ◽  
Quantum Annealing ◽  
Preliminary Assessment ◽  
New Variant ◽  
The Impact ◽  
The Physical Realization

In a recent paper, Lechner, Hauke, and Zoller (LHZ) described a means to translate a Hamiltonian ofNspin-1/2particles with “all-to-all” interactions into a larger physical lattice with only on-site energies and local parity constraints. LHZ used this mapping to propose a novel form of quantum annealing. We provide a stabilizer-based formulation within which we can describe both this prior approach and a wide variety of variants. Examples include a triangular array supporting all-to-all connectivity as well as arrangements requiring only 2NorNlogNspins but providing interesting bespoke connectivities. Further examples show that arbitrarily high-order logical terms can be efficiently realized, even in a strictly two-dimensional layout. Our stabilizers can correspond to either even-parity constraints, as in the LHZ proposal, or odd-parity constraints. Considering the latter option applied to the original LHZ layout, we note that it may simplify the physical realization because the required ancillas are only spin-1/2systems (that is, qubits rather than qutrits); moreover, the interactions are very simple. We make a preliminary assessment of the impact of these design choices by simulating small (few-qubit) systems; we find some indications that the new variant may maintain a larger minimum energy gap during the annealing process.

Formation of high temperature phase in flash-evaporated SnSe films

1990 ◽  
Vol 48 (4) ◽  
pp. 698-699
Author(s):  
J.P.S. Hanjra
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Energy Gap ◽  
Dominant Role ◽  
Fine Powder ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Water Mixture ◽  
Flash Evaporation ◽  
Photovoltaic Applications

Tin mono selenide (SnSe) with an energy gap of about 1 eV is a potential material for photovoltaic applications. Various authors have studied the structure, electronic and photoelectronic properties of thin films of SnSe grown by various deposition techniques. However, for practical photovoltaic junctions the electrical properties of SnSe films need improvement. We have carried out investigations into the properties of flash evaporated SnSe films. In this paper we report our results on the structure, which plays a dominant role on the electrical properties of thin films by TEM, SEM, and electron diffraction (ED).Thin films of SnSe were deposited by flash evaporation of SnSe fine powder prepared from high purity Sn and Se, onto glass, mica and KCl substrates in a vacuum of 2Ø micro Torr. A 15% HF + 2Ø% HNO3 solution was used to detach SnSe film from the glass and mica substrates whereas the film deposited on KCl substrate was floated over an ethanol water mixture by dissolution of KCl. The floating films were picked up on the grids for their EM analysis.

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