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The edges of graphene-based systems possess unusual electronic properties, originating from the non-trivial topological structure associated with the pseudospinorial character of the electron wavefunctions. These properties, which have no analogue for electrons described by the Schrödinger equation in conventional systems, have led to the prediction of many striking phenomena, such as gate-tunable ferromagnetism and valley-selective transport. In most cases, however, the predicted phenomena are not expected to survive the strong structural and chemical disorder that unavoidably affects the edges of real graphene devices. Here, we present a theoretical investigation of the intrinsic low-energy states at the edges of electrostatically gapped bilayer graphene, and find that the contribution of edge modes to the linear conductance of realistic devices remains sizable even for highly imperfect edges. This contribution may dominate over that of the bulk for sufficiently clean devices, such as those based on suspended bilayer graphene samples. Our results illustrate the robustness of those phenomena whose origin is rooted in the topology of the electronic band structure, even in the absence of specific protection mechanisms. [ABSTRACT FROM AUTHOR]

A discussion of recent work on time-dependent transport inmesoscopic structures is presented. The discussion emphasizesthe use of time-dependent transport to gain information on thecharge distribution and its collective dynamics. We discussthe RC-time of mesoscopic capacitors, the dynamic conductanceof quantum point contacts and dynamic weak localizationeffects in chaotic cavities. We review work on adiabaticquantum pumping and photon-assisted transport, and concludewith a list which demonstrates the wide range of problemswhich are of interest. [ABSTRACT FROM AUTHOR]

The article examines the possibility that positive and negative Coulomb drag can be switched by bringing two quantum wires within two-dimensional electron gases. It reference a study by Guillaume Gervais and colleagues at McGill University and Sandia National Laboratories, published in "Nature Nanotechnology." The researchers found that the drag resistance depends on the electron densities in both wires. It is stated that the study has implications for understanding circuit packing density.

Winful objects to our appeal to pulse reshaping discussed in refs 2,3. It is these discussions, however, that show that causality is maintained in the tunnelling process and that no fundamental tenet of modern physics is called into question. Although these discussions were put forth for short pulses, they are not, in principle, limited to this case. Indeed, pulse reshaping also occurs for long pulses, even if only at the leading edge of the pulse. [ABSTRACT FROM AUTHOR]