The lowest temperature achieved in a laboratory setting is extremely close to absolute zero, which is approximately -273.15 degrees Celsius or 0 Kelvin. Absolute zero is the point at which particles have the least amount of thermal energy and virtually no molecular motion.
Scientists have been able to reach temperatures very close to absolute zero using techniques such as laser cooling, evaporative cooling, and magnetic cooling. These methods involve removing heat energy from a system, resulting in the cooling of gases or materials. In 1995, researchers at the Massachusetts Institute of Technology (MIT) and the Joint Institute for Laboratory Astrophysics (JILA) achieved a temperature of 700 nanokelvins, which is just a fraction of a billionth of a degree above absolute zero.
However, it is important to note that absolute zero is a theoretical limit, and reaching it exactly is not currently possible. As per the laws of thermodynamics, it is believed that achieving absolute zero is unattainable due to the constant presence of residual energy and quantum mechanical effects. Nonetheless, scientists continue to push the boundaries of low-temperature research to explore the fascinating properties and behaviors of matter at extremely cold temperatures.