The term "Bose Metal", recently seen in the news, refers to:

The correct answer is option 2.

In News

• A research team from China and Japan recently found evidence that niobium diselenide (NbSe₂) may exhibit properties of a Bose metal, challenging traditional theories on metal conductivity at extremely low temperatures.

Key Points

• A Bose metal is an intermediate state between a normal metal and a superconductor, where conductivity increases at low temperatures but never reaches zero resistance. Hence, option 2 is correct.
• Conventional theories state that metals should either become superconductors (infinite conductivity) or insulators (zero conductivity) at absolute zero, but Bose metals defy this by maintaining conductivity between these extremes.
• Scientists observed in NbSe₂ that it improved conductivity but did not transition into a superconducting state.
• Hall resistance measurements confirmed that the material's charge carriers behaved differently from normal metals, supporting the Bose metal theory.

Additional Information

• Superconductors have zero electrical resistance at low temperatures.
• Bose metals remain conductive but never fully transition into superconductors.
• While Bose metals do not yet have practical applications, studying them helps scientists better understand quantum materials and phase transitions.