Mermin–Wagner theorem

Target entity: Mermin–Wagner theorem
Context triple: [Coleman theorem on symmetry breaking in two dimensions, relatedTo, Mermin–Wagner theorem]

• A. Kosterlitz–Thouless–Halperin–Nelson–Young theory
  The Kosterlitz–Thouless–Halperin–Nelson–Young theory is a framework in condensed matter physics that explains phase transitions in two-dimensional systems via topological defects and the unbinding of vortex–antivortex pairs, rather than conventional symmetry breaking.
• B. Coleman theorem on symmetry breaking in two dimensions
  The Coleman theorem on symmetry breaking in two dimensions is a result in quantum field theory stating that continuous symmetries cannot undergo spontaneous symmetry breaking in two-dimensional spacetime due to large infrared fluctuations.
• C. Landau–Peierls instability
  Landau–Peierls instability is a theoretical prediction in condensed matter physics that shows how long-wavelength thermal fluctuations destroy true long-range positional order in low-dimensional crystalline systems.
• D. Landau theory of second-order phase transitions
  Landau theory of second-order phase transitions is a phenomenological framework that explains continuous phase transitions by expanding the free energy in terms of an order parameter and analyzing symmetry-breaking behavior near critical points.
• E. Yang–Lee theory
  Yang–Lee theory is a framework in statistical mechanics and phase transition theory that studies the distribution of zeros of the partition function in the complex plane to understand critical phenomena.
• F. None of above. chosen
• G. Unsure - the case is ambiguous/there is not enough information to decide.

Target entity: Mermin–Wagner theorem
Target entity description: The Mermin–Wagner theorem is a fundamental result in statistical physics and quantum field theory stating that continuous symmetries cannot be spontaneously broken at finite temperature in one- and two-dimensional systems with short-range interactions, thereby forbidding long-range order such as conventional ferromagnetism in these low dimensions.

• A. Kosterlitz–Thouless–Halperin–Nelson–Young theory
  The Kosterlitz–Thouless–Halperin–Nelson–Young theory is a framework in condensed matter physics that explains phase transitions in two-dimensional systems via topological defects and the unbinding of vortex–antivortex pairs, rather than conventional symmetry breaking.
• B. Coleman theorem on symmetry breaking in two dimensions
  The Coleman theorem on symmetry breaking in two dimensions is a result in quantum field theory stating that continuous symmetries cannot undergo spontaneous symmetry breaking in two-dimensional spacetime due to large infrared fluctuations.
• C. Landau–Peierls instability
  Landau–Peierls instability is a theoretical prediction in condensed matter physics that shows how long-wavelength thermal fluctuations destroy true long-range positional order in low-dimensional crystalline systems.
• D. Landau theory of second-order phase transitions
  Landau theory of second-order phase transitions is a phenomenological framework that explains continuous phase transitions by expanding the free energy in terms of an order parameter and analyzing symmetry-breaking behavior near critical points.
• E. Yang–Lee theory
  Yang–Lee theory is a framework in statistical mechanics and phase transition theory that studies the distribution of zeros of the partition function in the complex plane to understand critical phenomena.
• F. None of above. chosen