The Discovery of Semi-Dirac Fermions: A New Chapter in Particle Physics

  • January 16, 2025
  • Posted by: OptimizeIAS Team
  • Category: DPN Topics
No Comments

 

 

The Discovery of Semi-Dirac Fermions: A New Chapter in Particle Physics

Sub: Sci

Sec: Space tech

Why in News

  • Physicists have identified a peculiar subatomic particle, the semi-Dirac fermion, which behaves uniquely under certain conditions. The discovery, made using a magnetic field 2.7 lakh times stronger than Earth’s, represents a significant development in particle physics. The findings were reported in a study conducted at Columbia University and Pennsylvania State University.

Standard Model of Particle Physics:

  • The Standard Model (SM) is a theoretical framework in particle physics that describes three of the four known fundamental forces in the universe—electromagnetic, weak, and strong interactions—and classifies all known elementary particles.
  • Developed in the early 1970s, it has been instrumental in explaining a wide range of experimental results and predicting new phenomena.
  • Fundamental Forces in the Standard Model:
Electromagnetic ForceWeak Nuclear ForceStrong Nuclear Force

 

Carrier Particle: Photon.

 

Carrier Particles: W and Z bosons.

 

Carrier Particle: Gluon.

 

Governs interactions between charged particles; responsible for electricity, magnetism, and light.Responsible for processes like beta decay in nuclear reactions; plays a crucial role in stellar fusion.

 

Binds quarks together to form protons and neutrons; holds atomic nuclei together.
  • Note: Gravity is not included in the Standard Model, as incorporating it has proven challenging.
  • Elementary Particles in the Standard Model: The Standard Model categorizes elementary particles into two main groups: fermions and bosons.
FermionsBosonsHiggs Boson
Particles that follow Fermi-Dirac statistics and obey the Pauli Exclusion Principle, making up matter (e.g., quarks and leptons).

Quarks:

Six flavours: up, down, charm, strange, top, bottom.

Combine to form hadrons (e.g., protons and neutrons).

Leptons:

Electron, muon, tau, and their corresponding neutrinos.

Particles that follow Bose-Einstein statistics and do not obey the Pauli Exclusion Principle, mediating fundamental forces (e.g., photons, gluons, and W/Z bosons).

Photon (electromagnetic force).

W and Z bosons (weak force).

Gluons (strong force).

Associated with the Higgs field; responsible for giving mass to other particles.

The Higgs mechanism explains how particles acquires mass. The Higgs field permeates the universe, and particles interacting with this field gain mass. The associated Higgs boson was experimentally confirmed in 2012 at CERN.

  • Types of Fermions:
    • Dirac Fermions: May or may not have mass. Distinct from their antiparticles.
    • Majorana Fermions: Identical to their antiparticles (e.g., neutrinos are suspected to belong to this class).

The Semi-Dirac Fermion: 

  • Has mass when moving in one direction but behaves as massless in a perpendicular direction.
  • Arises due to interactions with electric and magnetic fields in specific materials.
  • Semi-Dirac fermions are quasiparticles, which are groupings of particles or energy packets behaving like single particles under specific conditions.
  • Example: Protons (made of three quarks and gluons) are also quasiparticles.

Discovery Details:

  • Researchers used zirconium silicon sulphide (ZrSiS), a layered crystalline material.
  • Magnetic field strength of up to 5 tesla (270,000 times stronger than Earth’s magnetic field).
  • Materials like graphene and ZrSiS act as “mini-universes,” hosting exotic particles not observable in three-dimensional space.
  • Unlike subatomic particles discovered using large colliders like CERN’s Large Hadron Collider, semi-Dirac fermions were found in a lab-scale experiment.

Zirconium Silicon Sulphide (ZrSiS):

  • A layered crystalline material composed of zirconium (Zr), silicon (Si), and sulphur (S).
  • Exhibits unique scaling of cyclotron energy under a magnetic field, distinguishing it from other materials like graphene.
  • Helps in studying condensed matter physics and mimicking behaviours of subatomic particles in table-top experiments.
  • Provides insights into particle interactions and electronic properties under extreme conditions.
  • Advances the understanding of quantum materials. Useful in developing materials for electronics and quantum computing.
Science and tech The Discovery of Semi-Dirac Fermions: A New Chapter in Particle Physics