Reliable extraction of information from a physical system requires some combination of redundancy, state distinguishable, and access time. This has obvious implications for any prospective nanoelectronic technology that would require rapid extraction of information from small numbers of electrons through nanoscale access volumes. In this paper, we explore this issue through consideration of fundamental physical limits on information acquisition from electronic systems. We outline our general approach, obtain the required accessible information bounds for multipartitie information-bearing systems, and present model calculations that illustrate loss of accessible information at nanoscale access volumes and low particle densities in a simple tight-binding molecular wire. This approach, fully developed, could provide both useful physical insight and practical tools for the assessment of emerging electronic information processing technologies.
Reliable extraction of information from a physical system requires some combination of redundancy, state distinguishable, and access time. This has obvious implications for any prospective nanoelectronic technology that would require rapid extraction of information from small numbers of electrons through nanoscale access volumes. In this paper, we explore this issue through consideration of fundamental physical limits on information acquisition from electronic systems. We outline our general approach, obtain the required accessible information bounds for multipartitie information-bearing systems, and present model calculations that illustrate loss of accessible information at nanoscale access volumes and low particle densities in a simple tight-binding molecular wire. This approach, fully developed, could provide both useful physical insight and practical tools for the assessment of emerging electronic information processing technologies.
We consider fundamental limits on information acquisition from localized regions of molecular-scale electronic systems. Our approach is based on a quantitative measure we call the volume accessible information, defined as the (Shannon) mutual information associated with the best possible quantum measurement that can access a system through a specified readout volume. Using results and techniques from quantum measurement theory, we obtain a general expression for an upper bound on the volume accessible information that depends only on the manner in which information is encoded in electron states and specification of the readout volume. An illustrative study of a model tight-binding system indeed reveals that the volume accessible information is sharply reduced at small sampling volumes, where the state distinguishability required for reliable information extraction is diminished.
We consider fundamental limits on accessible information from molecular-scale volumes in electronic systems. Our approach is based on a quantitative measure—the volume accessible information—which we define as the Shannon mutual information associated with the best possible quantum measurement that can access a system through a specified readout volume. Specifically, we obtain a general expression for an upper bound on the volume accessible information that depends only on the manner in which information is encoded in electron states and specification of the readout volume. This bound is obtained within a tight-binding framework for simplicity and compatibility with atomistic descriptions of molecular-scale electronic systems. As an illustration, we study the volume accessible information bound for measurements accessing finite segments of long polyparaphenylene (PPP) molecules with binary information encoded in the states of electrons in the lowest unoccupied molecular orbital band. Evaluation of this bound reveals severe limits on the amount of information accessible from measurements on short PPP chain segments, where the state distinguishability required for reliable information extraction is diminished.
This paper studies fundamentals of classical, classical-quantum and quantum information technologies to advance sensing, data acquisition and computing. The overall goal is to define, analyze and evaluate classical and quantum-mechanical information measures pertained to data processing by low-power nanoelectronic devices, nanoICs, nano-waveguides, CMOS nanophotonics, etc. Electronic, optoelectronic and photonic systems operate on the electron- and photon-induced transductions. There are fundamental differences in physics, arithmetics, device- and system-level solutions as electrostatic and quantum phenomena are utilized. This paper analyzes multi-physics quantum↔classical processing. We enable a knowledge base in cognizant areas across computer science and engineering. Our findings enable existing and future communication, sensing, information fusion, computing and processing platforms. Consistent tools and practical schemes facilitate developments of novel engineering solutions, technical readiness, technological capabilities and commercialization capacities.
The thermodynamical behavior of quantum systems at the nanoscale is often very difficult to capture via standard frameworks of thermodynamics. The latter is, in fact, an equilibrium theory whose predictions are typically only valid on average, and in regimes where systems are composed of a very large number of constituents. In reality, the thermodynamical behavior of nanoscale systems can be much more constrained that what is predicted by macroscopic thermodynamics, due to the unavoidable impact of fluctuations. As a result, the fundamental limitations to a system's dynamics induced by macroscopic thermodynamics might turn out to be considerably less stringent than what can actually be observed at those scales. The theory of open quantum systems is certainly a powerful tool in this context, and can provide solutions which go beyond equilibrium treatments, but solving the dynamics of an open system requires detailed information about its microscopic structure (e.g. system-environment interactions and coupling strengths). In other words, one of the great advantages of macroscopic thermodynamics, i.e. its universality and independence of microscopic details, might be essentially lost if we can only infer thermodynamical results once we specify the full microscopic structure of our system-environment interaction. This highlights the necessity for a framework of thermodynamics that is well suited for studying the behavior of small quantum systems far from equilibrium, but can still be applied to physical systems in a universal way, i.e., without having to specify full microscopic information. Quantum Resource Theories (QRTs), and in particular the formulations of quantum thermodynamics that have emerged from them, constitute a promising tool in this direction. However, these models of thermodynamics have not yet been extensively applied to realistic physical platform, and their consequences on known thermodynamical processes are still unexplored. Furthermore, going beyond a purely thermodynamical context, a case can be made for the use of general QRTs as benchmarking tools for the certification of certain quantum resources. In other words, QRTs could be used to find fundamental bounds to physical quantities or impossibility results (in the form of no-go theorems) that, when compared to experimental data, can be used to falsify specific hypotheses. In this thesis, both these directions will be explored, by considering resource-theoretical questions that are relevant for different physical platforms. These will include the photochemical process of photoisomerization, heat transport in harmonic systems, and tabletop tests of quantum gravity.
For electronic, MEMS and electronic systems, we examine emerged technologies, research novel solutions and apply new transformative findings. To enable communication and processing schemes, nano and molecular technologies are applied. Transformative findings and developments are substantiated by analyzing and evaluating multi-physics microscopic systems. We advance physical foundations, engineering premises and information technology of classical, quantum and mixed sensing, communication and processing on quantum transductions. This paper examines fundamentals of quantum data processing on measurable and processable real-valued physical quantities. The developed paradigm: (1) Unifies and enables concepts of theoretical computer science, computer engineering and quantum mechanics; (2) Consistent with the first principles of quantum informatics, communication and processing; (3) Coherently examines device physics, switching algebra, processing arithmetics and calculus; (4) Enables practical microscopic hardware solutions for electronics, MEMS and electronic systems.
Microelectronics and the classical information technologies transformed the physics of semiconductors. Photonics has given optical materials a new direction. Quantum information technologies, we believe, will have immense impact on condensed matter physics. The novel systems of quantum information processing need to be designed and made. Their behaviours must be manipulated in ways that are intrinsically quantal and generally nanoscale. Both in this special issue and in previous issues (see e.g., Spiller T P and Munro W J 2006 J. Phys.: Condens. Matter 18 V1–10 ) we see the emergence of new ideas that link the fundamentals of science to the pragmatism of market-led industry. We hope these papers will be followed by many others on quantum information processing in Journal of Physics: Condensed Matter .