Quantum Dot Cellular Automata
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2022 ◽  
Vol 2161 (1) ◽  
pp. 012025
B.S. Premananda ◽  
T.N. Dhanush ◽  
Vaishnavi S. Parashar

Abstract Quantum-dot Cellular Automata (QCA) is a transistor-less technology known for its low power consumption and higher clock rate. Serial Concatenated Convolutional Coding (SCCC) encoder is a class of forward error correction. This paper picturizes the implementation of the outer encoder as a (7, 4, 1) Bose Chaudhary Hocquenghem encoder that serves the purpose of burst error correction, a pseudo-random inter-leaver used for permuting of systematic code words and finally the inner encoder which is used for the correction of random errors in QCA. Two different architectures of the SCCC encoder have been proposed and discussed in this study. In the proposed two architectures, the first based on external clock signals whereas the second based on internal clock generation. The sub-blocks outer encoder, pseudo-random inter-leaver and inner encoder of the SCCC encoder are optimized, implemented and simulated using QCADesigner and then integrated to design a compact SCCC encoder. The energy dissipation is computed using QCADesigner-E. The proposed SCCC encoder reduced the total area by 46% and energy dissipation by 50% when compared to the reference SCCC encoder. The proposed encoders are more efficient in terms of cell count, energy dissipation and area occupancy respectively.

Н. Патак ◽  
Н. К. Мисра ◽  
Б. К. Бхои ◽  
С. Кумар

По сравнению с полевыми транзисторами, имеющими структуру «металл–оксид–полупроводник» (МОП-структура), клеточные автоматы на квантовых точках, или квантовые клеточные автоматы QCA (quantum-dot cellular automata) обеспечивают большие преимущества. В статье рассмотрена реализация с помощью технологии QCA цифровых схем, таких как полный сумматор, мультиплексор, сумматор с запоминанием переноса, сумматор с переключением переноса, сумматор с пропуском переноса, и устройство быстрого сдвига для получения надежной архитектуры устройств в области наноэлектроники. Цель состоит в том, чтобы получить концептуальную схему для оптимизации QCA конструкций с использованием копланарных ячеек, что является достаточно гибким решением для использования при конструировании сложных систем. В результате этого синтеза получены новые конструкции, которые пригодны для создания наноэлектронных схем. Для проверки цифровых схем в синтезированных конструкциях, представленных в этой статье, использовался пакет разработки и моделирования QCADesigner. Среда моделирования QCA использована для верификации конструкций, определения параметров, и выполнения цифровых вычислений. Главная цель этой работы состоит в разработке конструкции робастного сумматора в терминах ограниченной площади ячейки, и других стоимостных элементов. Использован копланарный метод для построения QCA топологии различных сумматоров, который является более эффективным и компактным. Результаты сравнения показали, что использование новых цифровых конструкций обеспечивает лучшие результаты, и обеспечивает более надежную архитектуру, по сравнению с существующими конструкциями.

2021 ◽  
Vol 11 (24) ◽  
pp. 12157
Mohsen Vahabi ◽  
Pavel Lyakhov ◽  
Ali Newaz Bahar ◽  
Khan A. Wahid

The miniaturization of electronic devices and the inefficiency of CMOS technology due to the development of integrated circuits and its lack of responsiveness at the nanoscale have led to the acquisition of nanoscale technologies. Among these technologies, quantum-dot cellular automata (QCA) is considered one of the possible replacements for CMOS technology because of its extraordinary advantages, such as higher speed, smaller area, and ultra-low power consumption. In arithmetic and comparative circuits, XOR logic is widely used. The construction of arithmetic logic circuits using AND, OR, and NOT logic gates has a higher design complexity. However, XOR gate design has a lower design complexity. Hence, the efficient and optimized XOR logic gate is very important. In this article, we proposed a new XOR gate based on cell-level methodology, with the expected output achieved by the influence of the cells on each other; this design method caused less delay. However, this design was implemented without the use of inverter gates and crossovers, as well as rotating cells. Using the proposed XOR gate, two new full adder (FA) circuits were designed. The simulation results indicate the advantage of the proposed designs compared with previous structures.

2022 ◽  
Vol 97 ◽  
pp. 107638
Arindam Sadhu ◽  
Kunal Das ◽  
Debashis De ◽  
Maitreyi Ray Kanjilal

2021 ◽  
Nishattasnim Liza ◽  
Dylan Murphey ◽  
Peizhong Cong ◽  
David W. Beggs ◽  
Yuihui Lu ◽  

Abstract Mixed-valence compounds may provide molecular devices for an energy-efficient, low-power, general-purpose computing paradigm known as quantum-dot cellular automata (QCA). Multiple redox centers on mixed-valence molecules provide a system of coupled quantum dots. The configuration of mobile charge on a double-quantum-dot (DQD) molecule encodes a bit of classical information robust at room temperature. When arranged in non-homogeneous patterns (circuits) on a substrate, local Coulomb coupling between molecules enables information processing. While single-electron transistors (SETs) and single-electron boxes (SEBs) could provide low-temperature solutions for reading the state of a 1-nm-scale molecule, we propose a room-temperature read-out scheme. Here, DQD molecules are designed with slightly dissimilar quantum dots. Ab initio calculations show that the binary device states of an asymmetric molecule have distinct Raman spectra. Additionally, the dots are similar enough that mobile charge is not trapped on either dot, allowing device switching driven by the charge configuration of a neighbor molecule. A technique such as tip-enhanced Raman spectroscopy (TERS) could be used to detect the state of a circuit comprised of several QCA molecules.

2021 ◽  
Vol 0 (0) ◽  
Saumya Srivastava ◽  
Upendra Chaurasiya ◽  
Pradeep Tiwari ◽  
Ashish Misal ◽  
Kamal Kishor Upadhyay

Abstract The construction of an all-optical frequency-encoded Toffoli gate employing a reflecting semiconductor optical amplifier (RSOA) is proposed in this article. By establishing fields such as quantum computing, optical quantum computing, quantum-dot cellular automata, and superconducting flux logic family, quantum gates have been proved to perform reliably in the present day. A nonzero-mass electron, on the other hand, moves far slower than a quantum particle with zero rest mass, such as a photon. Photons can also be utilized to store data while being sent. These photon qualities have motivated researchers to create quantum gates in the all-optical domain based on them. The RSOA-based implementation of the Toffoli gate gives a significant improvement in the case of high speed, low power, and fast switching time. MATLAB Simulink (R2018a) software is used to simulate the devised design. The theoretical prediction is satisfied by the simulation results.

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