Quantum Computing: Theoretical versus Practical Possibility

Andreas H. Trabesinger

Gheorghe Sorin Paraoanu

An intense effort is being made today to build a quantum computer. Instead of presenting what has been achieved, I invoke analogies from the history of science in an attempt to glimpse what the future might hold. Quantum computing is possible in principle—there are no known laws of Nature that prevent it—yet scaling up the few qubits demonstrated so far has proven to be exceedingly difficult. While this could be regarded merely as a technological or practical impediment, I argue that this difficulty might be a symptom of new laws of physics waiting to be discovered. I distinguish between ‘‘strong’’ and ‘‘weak’’ emergentist positions. The former assumes that a critical value of a parameter exists (one that is most likely related to the complexity of the states involved) at which the quantum-mechanical description breaks down, in other words, that quantum mechanics will turn out to be an incomplete description of reality. The latter assumes that quantum mechanics will remain as a universally valid theory, but that the classical resources required to build a real quantum computer scale up with the number of qubits, which hints that a limiting principle is at work.

D. Frolov, Sudipto Chakraborty, Devin Underwood +18 more

Cryogenic CMOS control and readout electronics for quantum computing using superconducting qubits offers several potential advantages versus the use of room temperature electronics, including reduced wiring and lower cost per control channel. The development and practical implementation of such electronics at a mass-production scale for systems with tens of thousands of channels, however, requires circuit characterization in the target cryogenic use environment and with interfaces as close as possible to those that will be used in a real quantum machine. The cryogenic use environment and interfaces for test are usually far from the almost ideal conditions that can be achieved in a regular cryogenic probe station. In this paper, we describe a new testbed for the characterization of CMOS circuits at cryogenic temperatures that solves some of these problems.

Stefano Patarnello

Varsha J. Patil, Mayuri B. Babar, Gitanjali N. Pawar

The evolution of quantum computing poses a profound challenge to traditional cryptographic systems based on number-theoretic assumptions such as integer factorization and discrete logarithms. This paper presents a comparative analysis between lattice-based and group-theoretic cryptographic schemes, two promising post-quantum approaches. The study highlights their mathematical foundations, underlying hardness assumptions, and operational principles. Furthermore, practical examples such as NewHope and Ko–Lee key exchange protocols are examined to illustrate the working mechanisms of both paradigms. The findings indicate that lattice-based cryptography demonstrates superior quantum resistance, efficiency, and standardization potential, whereas group-theoretic cryptography remains primarily theoretical but offers fertile ground for future innovations.

Habiba Drias, Farouk Yalaoui