arXiv subjects

Roman Shapira

Publications and source records attributed to Roman Shapira.

4 recordsLinked to original sources

arXiv2024

Design and synthesis of scalable quantum programs

We present a scalable, robust approach to creating quantum programs of arbitrary size and complexity. The approach is based on the true abstraction of the problem. The quantum program is expressed in terms of a high-level model together with constraints and objectives on the final program. Advanced synthesis algorithms transform the model into a low-level quantum program that meets the user's specification and is directed at a stipulated hardware. This separation of description from implementation is essential for scale. The technology adapts electronic design automation methods to quantum computing, finding feasible implementations in a virtually unlimited functional space. The results show clear superiority over the compilation and transpilation methods used today. We expect that this technological approach will take over and prevail as quantum software become more demanding, complex, and essential.

quant-ph↗

arXiv2021

Digital signatures with Quantum Candies

Quantum candies (qandies) is a pedagogical simple model which describes many concepts from quantum information processing (QIP) intuitively, without the need to understand or make use of superpositions, and without the need of using complex algebra. One of the topics in quantum cryptography which gains research attention in recent years is quantum digital signatures (QDS), involving protocols to securely sign classical bits using quantum methods. In this paper we show how the "qandy model" can be used to describe three QDS protocols, in order to provide an important and potentially practical example of the power of "superpositionless" quantum information processing, for individuals without background knowledge in the field.

quant-ph↗

arXiv2021

Quantum information and beyond -- with quantum candies

The field of quantum information is becoming more known to the general public. However, effectively demonstrating the concepts underneath quantum science and technology to the general public can be a challenging job. We investigate, extend, and greatly expand here "quantum candies" (invented by Jacobs), a pedagogical model for intuitively describing some basic concepts in quantum information, including quantum bits, complementarity, the no-cloning principle, and entanglement. Following Jacob's quantum candies description of the well-known quantum key distribution protocol BB84, we explicitly demonstrate additional quantum cryptography protocols and quantum communication protocols, using generalized quantum candies (including correlated pairs of qandies). These demonstrations are done in an approachable manner, that can be explained to high-school students, without using the hard-to-grasp concept of superpositions and its mathematics. The intuitive model we investigate has a fascinating overlap with some of the most basic features of quantum theory. Hence, it can be a valuable tool for science and engineering educators who would like to help the general public to gain more insights into quantum science and technology. For the experts, the model we present, due to not employing quantum superpositions, enables - in some sense - extending far beyond quantum theory. Most remarkably, "quantum" candies of some unique type can be defined, such that non-local boxes (of the Popescu-Rohrlich type) as well as regular (correlated) quantum candies can be generated by a single `"quantum" candies machine.

physics.ed-ph↗

arXiv2021

Non-NP-Hardness of Translationally-Invariant Spin-Model Problems

Finding the ground state energy of the Heisenberg Hamiltonian is an important problem in the field of condensed matter physics. In some configurations, such as the antiferromagnetic translationally-invariant case on the 2D square lattice, its exact ground state energy is still unknown. We show that finding the ground state energy of the Heisenberg model cannot be an NP-Hard problem unless P=NP. We prove this result using a reduction to a sparse set and certain theorems from computational complexity theory. The result hints at the potential tractability of the problem and encourages further research towards a positive complexity result. In addition, we prove similar results for many similarly structured Hamiltonian problems, including certain forms of the Ising, t-J, and Fermi-Hubbard models.

cs.CC↗