Quantum Computation and Logic

László B. Kish

Exponential parallelism, a defining principle of advanced computational systems, holds promise for transformative impacts across several scientific and industrial domains. This feature paper provides a comparative overview of Quantum Computing (QC) and Instantaneous Noise-based Logic (INBL), focusing on their practical strengths, limitations, and applications rather than exhaustive technical depth. Both paradigms leverage exponentially large Hilbert spaces: quantum computing achieves this via quantum superposition, while INBL realizes it through the product space of classical noise processes. Quantum computers attain universality for all computational operations, whereas current INBL frameworks are universal only for Boolean logic; notably, essential superposition operations-such as AND and OR gates-are absent, precluding implementations of algorithms like Shor's. However, for certain problem classes where full universality is not required, INBL and quantum computing can offer equivalent time and hardware complexity, as observed with the Deutsch-Jozsa algorithm. Remarkably, for search tasks such as phonebook lookup, Grover's quantum algorithm provides a quadratic O(n^0.5) speedup compared to the classical approach, while INBL achieves an exponential speedup, requiring only logarithmic time in the size n of the phonebook O(log n). Such INBL algorithms could, in principle, be adapted to quantum hardware to attain similar performance. Importantly, INBL hardware is considerably simpler, being implementable with modest modifications to conventional PC architectures equipped with a true random number generator, and it inherently avoids the decoherence and error correction challenges of quantum systems.

Mladen Pavičić, Norman D. Megill

Stanley Gudder

László B. Kish

Exponential parallelism, a defining principle of advanced computational systems, holds promise for transformative impacts across several scientific and industrial domains. This feature paper provides a comparative overview of Quantum Computing (QC) and Instantaneous Noise-based Logic (INBL), focusing on their practical strengths, limitations and applications rather than exhaustive technical depth. Both paradigms leverage exponentially large Hilbert spaces: QC achieves this via quantum superposition, while INBL realizes it through the product space of classical noise processes. Quantum computers attain universality for all computational operations, whereas current INBL frameworks are universal only for Boolean logic; notably, essential superposition operations — such as AND and OR gates — are absent, precluding implementations of algorithms like Shor’s. However, for certain problem classes where full universality is not required, INBL and QC can offer equivalent time and hardware complexity, as observed with the Deutsch–Jozsa algorithm. Remarkably, for search tasks such as phonebook lookup, Grover’s quantum algorithm provides a quadratic [Formula: see text] speedup compared to the classical approach, while INBL achieves an exponential speedup, requiring only logarithmic time in the size N of the phonebook [Formula: see text]. Such INBL algorithms could, in principle, be adapted to quantum hardware to attain similar performance. Importantly, INBL hardware is considerably simpler, being implementable with modest modifications to conventional PC architectures equipped with a true random number generator, and it inherently avoids the decoherence and error correction challenges of quantum systems.

A. Kamaraj, P. Marichamy

In the current scenario, power consumption, speed, size and heat dissipation are the huge challenge in the semiconductor industries. When the size of the single computing element is reduced then the speed can be improved and also if the power dissipation is reduced then the heat dissipation will be less. The possible solution for these two problems is the Reversible Logic and Quantum Cellular Automata (QCA). The Reversible Logic is considered to be the promising technology to the future Quantum computer technologies. The Reversible Logic gates prune the power dissipation to a larger extent. In this paper Novel Reversible Gates are proposed with Reversibility and Universality. The Arithmetic and Logic Unit (ALU) is designed with the proposed Reversible Gates in Reversible Logic. The designed Arithmetic and Logic unit is evaluated in QCA with the required specifications. The Arithmetic and Logic Unit is designed by setting the control inputs for each unit. The parameters taken into account are Quantum Cost (QC), Garbage Outputs (GO), Constant Inputs (CI), Area, Number of Cells and Simulation Time. The proposed ALU adopting Novel gates finds utilization in low power applications. Also it can be used as the module in the Quantum computers due to its reduced Quantum Cost and Garbage outputs. The Proposed design extends its applications over Quantum Computing, Optical Computing, Nanotechnology and DNA mapping.

M. Dalla Chiara, Roberto Giuntini, Richard J. Greechie