Chemical bonding is the process by which atoms connect with each other to form molecules and compounds. It involves the interactions between the electrons of different atoms, allowing them to achieve greater stability. There are several types of chemical bonds, the most common being: 1. **Ionic Bonds**: Formed when one atom donates an electron to another, resulting in the formation of positively and negatively charged ions (cations and anions).

Correlated electrons refer to electrons in a material that exhibit strong interactions with each other, leading to collective behavior that cannot be adequately described by treating them as independent particles. In systems of interacting electrons, the motions and states of individual electrons become dependent on one another, resulting in complex phenomena that are not captured by the simple principles of non-interacting particle physics.

Electronic band structures describe the range of energies that electrons can have in a solid material and the corresponding ranges of energies that they cannot have, often referred to as "forbidden bands" or "band gaps." The band structure is a fundamental concept in solid-state physics and is crucial for understanding the electronic properties of materials, including conductors, semiconductors, and insulators.

Laboratory techniques in condensed matter physics involve various experimental methods used to study the properties and behaviors of condensed matter systems, which include solids and liquids. These techniques aim to investigate the microscopic and macroscopic characteristics of materials, often at the atomic or molecular level.

Semiconductor properties refer to the characteristics and behaviors of semiconductor materials, which are crucial in the fields of electronics and optoelectronics. Semiconductors have unique electrical properties that allow them to conduct electricity under certain conditions while acting as insulators under others. Here are some key properties of semiconductors: 1. **Band Gap**: Semiconductors have a band gap between the valence band (where electrons are bound) and the conduction band (where electrons can move freely).

Water physics is a branch of physics that specifically studies the properties, behavior, and interactions of water in various states (liquid, solid, and gas) and under different conditions. It encompasses a wide range of topics, including: 1. **Fluid Dynamics**: Understanding how water flows and behaves as a fluid, including concepts such as viscosity, turbulence, laminar flow, and the principles of hydrostatics and hydrodynamics.

The Josephson effect is a quantum mechanical phenomenon observed in superconductors, where a supercurrent flows between two superconductors separated by a thin layer of insulator or a nonsuperconducting material, often referred to as a Josephson junction. This effect was first predicted by the physicist Brian D. Josephson in 1962 and has since become fundamental to various applications in superconducting electronics.

A Sachs subgraph is a concept from graph theory, specifically in the context of combinatorial structures and properties related to planar graphs. It refers to a type of subgraph that is constructed from a planar graph in such a way that certain conditions are met. In more detail, a Sachs subgraph is typically defined for a planar graph as a spanning subgraph that respects the original graph's facial structures in a certain way.