Mesoscopic physics

Mesoscopic physics is a branch of condensed matter physics that studies systems whose size is on the order of the mean free path of electrons, typically ranging from a few nanometers to a few micrometers. At this scale, materials exhibit unique properties that differ significantly from those of bulk materials and from individual atoms or molecules. Key features and concepts in mesoscopic physics include: 1. **Quantum Coherence**: In mesoscopic systems, quantum effects become significant, and electrons can exhibit wave-like behavior.

Coulomb blockade is a quantum mechanical phenomenon that occurs in small conductive structures, such as small metal or semiconductor particles (quantum dots) or single-electron transistors. It is characterized by the suppression of electrical conduction due to the electrostatic repulsion between charged particles—specifically, electrons. In a typical scenario, when an electron is added to a small conductor, it experiences a Coulomb energy barrier due to the presence of other electrons already in the conductor.

Ionic Coulomb blockade refers to a transport phenomenon observed in systems where ionic charge carriers (such as ions in an electrolyte) are confined within a nanoscale system, often resembling the more widely studied electronic Coulomb blockade observed in mesoscopic systems. In the typical electronic Coulomb blockade, the conduction of electrons through quantum dots or small conductive islands is inhibited when the energy required to add an extra electron to the island exceeds the available thermal energy.

The Landauer formula is a key result in the field of quantum transport and statistical mechanics, particularly in the study of electronic transport in mesoscopic systems. It relates the conductance or current through a quantum system to its transmission properties. The formula is named after Rolf Landauer, who introduced it in the 1950s to describe how information loss in a system is related to energy dissipation in electronic circuits.

Levitated optomechanics is a field of research that combines aspects of optomechanics and optical trapping to study the interaction between light and mechanical systems at the quantum level. In this context, "optomechanics" refers to the study of how light (photons) can affect mechanical motion (like vibrations of a mirror or a cantilever) and vice versa. In classical optomechanics, mechanical systems are typically coupled to optical cavities, where light allows for the manipulation of mechanical elements.

The Meir-Wingreen formula is a theoretical result in the field of quantum transport, particularly in the study of electron transport through mesoscopic systems, such as quantum dots or quantum wires. It provides a way to calculate the current flowing through a system under the influence of an applied voltage. The formula relates the current through a conductor to the scattering properties of the system and the density of states of the leads (the reservoirs connected to the conductor) and the energy levels of the conductor.

A nanowire is a nanoscale wire with a diameter typically on the order of nanometers (1 to 100 nanometers) and can be made from a variety of materials, including metals, semiconductors, and insulators. These materials exhibit unique electrical, optical, and mechanical properties at the nanoscale, making nanowires of great interest in a variety of scientific and technological fields.

Bacterial nanowires, also known as microbial nanowires or bacterial nanofibers, are thin, electrically conductive appendages produced by certain species of bacteria. These structures are primarily made up of protein and are capable of conducting electrons, enabling direct electron transfer between the bacteria and external surfaces, such as electrodes or other bacteria. **Key Characteristics and Functions:** 1.

Nanowire lasers are a type of laser that utilize nanowire structures as the gain medium. These nanowires, typically made from semiconductor materials, have diameters on the nanometer scale (usually between a few tens of nanometers to a few hundred nanometers) and can be several micrometers long.

Persistent current refers to a phenomenon observed in certain types of superconductors, particularly in the context of mesoscopic systems and finite-sized superconductors. It describes a continuous flow of electric current that persists without any applied voltage, even in the absence of a traditional power source. This effect is a consequence of superconductivity, a state of matter characterized by zero electrical resistance and the expulsion of magnetic fields.

A quantum dot is a nanoscale semiconductor particle that has quantum mechanical properties. Typically ranging from 2 to 10 nanometers in size, quantum dots are so small that their electronic characteristics are dominated by quantum effects. This feature causes them to exhibit unique optical and electronic properties, such as size-dependent light emission. ### Key Characteristics of Quantum Dots: 1. **Quantum Confinement**: Quantum dots exhibit quantum confinement effects, which means that the energy levels within them are quantized.

A Quantum Point Contact (QPC) is a nanoscale structure that allows the study of quantum transport phenomena in one-dimensional conductors. It is typically formed in a two-dimensional electron gas (2DEG) system, often created in semiconductor heterostructures. The QPC can be thought of as a narrow constriction through which electrons can tunnel, and its width can be controlled with high precision. **Key Features of Quantum Point Contacts:** 1.

A quantum wire is a nanoscale structure in which charge carriers, such as electrons, are confined to move in one dimension, effectively creating a "wire" with quantum mechanical properties. This confinement leads to quantization of energy levels and results in unique electronic and optical behaviors that are not observed in bulk materials.

Shot noise is a type of electronic noise that arises from the discrete nature of charge carriers, such as electrons, in a system. It is particularly significant in situations where current is low, and it becomes more pronounced in semiconductor devices, photodetectors, and other electronic components that rely on the movement of individual charge carriers.