After decades of pure science phase, the research on quantum technologies is finally reaching the engineering phase, getting out of the labs into business reality. Quantum technologies relies on quantum bits, aka qubits, which are the equivalent of classical bits used in classical information processing. Similarly to bits, the information stored in qubits can be corrupted by classical noise. Differently from bits, qubits are also vulnerable to quantum noise, a type of noise with no counterpart in the classical world. Hence, it becomes crucial to understand, from an engineering perspective, how the quantum noise corrupts the information stored within a qubit. To this aim, in this invited paper, we overview the effects of the quantum noise on an arbitrary qubit from a signal-processing perspective.
After decades of pure science phase, the research on quantum technologies is finally reaching the engineering phase, getting out of the labs into business reality. Quantum technologies relies on quantum bits, aka qubits, which are the equivalent of classical bits used in classical information processing. Similarly to bits, the information stored in qubits can be corrupted by classical noise. Differently from bits, qubits are also vulnerable to quantum noise, a type of noise with no counterpart in the classical world. Hence, it becomes crucial to understand, from an engineering perspective, how the quantum noise corrupts the information stored within a qubit. To this aim, in this invited paper, we overview the effects of the quantum noise on an arbitrary qubit from a signal-processing perspective.
Most of the publications on Quantum Computing and its main building block; the Qubit, rely on the Quantum Theory and use its terminologies. It is therefore not an easy task for the Electrical Engineers to fully understand the concept of the qubits, and how they are designed, controlled, readout, and used for computation. The primary aim of this paper is to show that the physical quantities describing the superconducting Transmons-the microwave realizations of the qubits-are just noisy signals similar to those encountered in e.g. Mobile and Satellite Communications. The nature of the noise in the qubit case, which will be simply called Quantum Noise, is essentially different from that of e.g. the thermal one. Contrary to the well-studied Thermal Noise, the Quantum one enjoys precise probability distributions and can interfere coherently. In particular, the so-called Stationary States resemble individually pure noise. However, a superposition of at least two of them results in a noisy signal, whose signal-to-noise ratio improves (goes higher) as more stationary states enter the superposition. Furthermore, the excitation (control) and readout of the qubits will be treated from the perspectives of the Electrical Engineering.
Internet just turned 50: five decades that shaped the world we live in. Indeed, Internet itself evolved astonishingly since the beginning, from a network prototype consisting of a few static nodes in the early days to a leviathan interconnecting with billions of devices half of the world’s population. Yet the fundamental assumption underlying Internet’s design – i.e., transmitting messages that can be encoded in a sequence of classical bits – remained unchanged during these five decades. But the dawn of the engineering phase of quantum technologies is challenging Internet’s fundamental assumption. Quantum devices demand for communication primitives – namely, the ability to distribute entangled states and to transmit quantum information – governed by the laws of quantum mechanics. Hence, principles and phenomena with no counterpart in classical networks require a major network-paradigm shift to harness the quantum mechanics specificities. This presentation aims at shedding light on the challenges and the open problems arising with the design of a protocol stack for the Quantum Internet.
The advanced notebooks, mobile phones, and internet applications in today’s world that we use are all entrenched in classical communication bits of zeros and ones. Classical internet has laid its foundation originating from the amalgamation of mathematics and Claude Shannon’s theory of information. However, today’s internet technology is a playground for eavesdroppers. This poses a serious challenge to various applications that rely on classical internet technology, and it has motivated the researchers to switch to new technologies that are fundamentally more secure. By exploring the quantum effects, researchers paved the way into quantum networks that provide security, privacy, and range of capabilities such as quantum computation, communication, and metrology. The realization of Quantum Internet (QI) requires quantum communication between various remote nodes through quantum channels guarded by quantum cryptographic protocols. Such networks rely upon quantum bits (qubits) that can simultaneously take the value of zeros and ones. Due to the extraordinary properties of qubits such as superposition, entanglement, and teleportation, it gives an edge to quantum networks over traditional networks in many ways. At the same time, transmitting qubits over long distances is a formidable task and extensive research is going on satellite-based quantum communication, which will deliver breakthroughs for physically realizing QI in near future. In this paper, QI functionalities, technologies, applications and open challenges have been extensively surveyed to help readers gain a basic understanding of the infrastructure required for the development of the global QI.
In the endless striving to push the boundaries of information processing capabilities, the competition that rages today between Quantum Bits and Classical Bits has become the central area of interest in modern research. The research elucidates and analyzes the distinct characteristics of these two fundamental units of information. It also critically examines their prospective futures in computing. In this article, a comprehensive comparison between Classical Bits - the binary entities that constituted classical computing for decades - and quantum bits - quantum mechanical counterparts that realize the principles of superposition and entanglement - is given. The research is based on the fundamental principles of classical and quantum computers, information units, logic circuits, time scaling dissimilarities, and complexity of algorithms. This article fills this gap by providing a comprehensive and structured comparative analysis of Classical Bits and quantum bits, examining their foundational principles, logic circuit realizations, algorithmic complexity, and computational scalability. The study offers a consolidated perspective that helps clarify the fundamental differences and practical implications of classical versus quantum computation, thereby supporting researchers and practitioners in understanding the computational advantages and limitations of both paradigms. Key observations include: The world has witnessed that classical computers have emerged vastly over the decades, in terms of memory sizes and computing speeds. For this reason, classical computers are used in nearly all fields. Nevertheless, in many fields, classical computers are less effective in solving complex problems in terms of accuracy, speed, and efficiency. Therefore, research exploring the exceptional features - entanglement and superposition - of qubits or Quantum Bits explores how quantum phenomena give rise to new modalities in computing.
Quantum computing algorithms are usually built by using gates and circuits to manipulate qubits. In this article, our analysis examines the impact of additive noise in a quantum circuit as an engineering simplification model. We evaluate these effects by computing the probability, fidelity, and signal-to-noise ratio (SNR). We study quantum noise from an amplitude-domain signal-processing perspective, bridging classical additive noise models with quantum state perturbations. We have analyzed the results of various quantum gates, such as X, Y, Z, and Hadamard gates. This study provides an approximation of the quantitative effect and qualitative analysis of the effect of additive noise on quantum gates, thereby contributing to a deeper understanding of the challenges and potential solutions in quantum computing. However, in some cases, the model does not represent the physical results due to approximation.
Breakthrough developments in quantum information technology is paving the way to the Quantum Internet. This article aims to provide an overview of the current state of research and development in the field of Quantum Communications and Quantum Internet. We examine the main building blocks and the latest achievements. By providing a holistic overview of recent achievements, this article fosters a deeper understanding of these building blocks, the related opportunities, and challenges associated with the realization of the Quantum Internet. We also provide some simple pedagogical models aimed to give the reader a clear insight on the interactions between quantum networking elements. A simple Quantum Internet 5Level-3D communication model is also provided, which integrates with, rather than parallels, the classical OSI and TCP/IP models. We further describe deployed testbeds and trials and highlight potential opportunities and challenges for Communication Service Provider's. We also provide some KPIs of quantum technologies and their evolution over the last decade. This article is intended as a self-contained entry level tutorial for newcomers who are not familiar with quantum information theory, but with some background knowledge about classical networking. Academics, students, as well as professionals can use this article to become able to begin researching the Quantum Internet, without having to read a plethora of articles, web pages, and books on the subject.