Phonons on the chopping block: Are ‘sound particles’ quantum too?


  • Quantum computers and artificial intelligence are two of the emerging areas of interest in the realm of computing. Recently, IBM published a paper in which it claimed to have demonstrated that a quantum computer could solve a useful problem that today’s conventional computers can’t, a result merited by concerns that their computations might become too unreliable when they also become complicated.

Defining qubits

  • Quantum computers use qubits as their basic units of information.
  •  A qubit can be a particle — like an electron; a collection of particles; or a quantum system engineered to behave like a particle.
  • Particles can do funky things that large objects, like the semiconductors of classical computers, can’t because they are guided by the rules of quantum physics.
  • The premise of quantum computing is that information can be ‘encoded’ in some property of the particle, like an electron’s spin, and then processed using these peculiar abilities.
  • As a result, quantum computers are expected to perform complicated calculations that are out of reach of the best supercomputers of today.
  • Other forms of quantum computing use other units of information. For example, linear optical quantum computing (LOQC) uses photons, the particles of light, as qubits.

Understanding phonons

  • Physicists thus wondered whether they can use phonons as qubits.
  • Photons are packets of light energy; similarly, phonons are packets of vibrational energy.
  • While researchers can manipulate electrons using electric currents, magnetic fields, etc. and photons with mirrors, lenses, etc, they needed new tools to manipulate phonons.
  • Beam-splitters are used widely in optics research. Imagine a torchlight shining light along a straight line. This is basically a stream of photons.
  • When a beam-splitter is placed in the light’s path, it will split the beam into two, that is, it will reflect 50% of the photons to one side and let the other 50% pass straight through.
  • When  the single wave interacts with the beam-splitter, it enters a superposition of the two possible outcomes — reflected and transmitted. When these states recombine, an interference pattern shows up.

Types of Phonon

When the unit cell consists of more than one atom, the crystal will contain two types of phonons. Thus, there are two types of phonons that we study in condensed matter physics:

  • Acoustic Phonon: In acoustic phonons, both positive and negative ions swing together.
  • Optical Phonon: In optical phonons, both positive and negative ions swing against each other. The optical phonons are excited easily by light.

Properties of Phonons

  • Phonons are often used as a quasiparticle, some popular research has shown that phonons and protons may indeed have some kind of mass and be affected by gravity.
  • phonons are said to have a kind of negative mass and negative gravity.
  • phonons are known to travel faster (with maximum velocity) in denser materials.
  • It is projected that phonons would deflect away as it detects the difference in densities, exhibiting the qualities of a negative gravitational field.
  • Phonons have also been predicted to play a key role.
  • They can also be used as quasiparticles.
  • They can be affected by gravity.
  • They tend to have negative energy and negative mass.
  • They travel faster in denser material (with higher velocity).


  • Phonon is an important topic of study in solid state physics and condensed matter physics. It is studied because, most physical structures such skyscrapers, are subjected to crystal vibrations. This vibrations are direct consequence of phonon. Therefore, as a physicists and engineers, we can regulate the strength of vibrations by calculating a good estimate of relations between, frequency, wave vector, and energy. Therefore, studying phonon is encouraged.

Editorial 2: Refugees as assets to their new countries


  • As we commemorate yet another World Refugee Day (June 20), we honour the courage and resilience of the 103 million individuals who have endured forced displacement due to conflicts and unrest worldwide. These staggering figures mask countless human stories marked by loss and shattered dreams.

Importance of the day

  • This day is a reminder of our collective responsibility as global citizens and a call for engagement and empathy.
  • It is a day to promote solidarity between communities, and, most importantly, to reflect on the importance of welcoming refugees and displaced persons into our communities.
  • Global conflicts which include the ongoing wars in Ukraine, Myanmar and Sudan among others, and the protracted situations in Afghanistan, and Somalia present an unprecedented challenge.
  • Sadly, South and Southeast Asia are not immune to the challenges of displacement. India is home to some 250,000 forcibly displaced persons, with women and children constituting half of that population.
  • India continues to graciously host and assist refugees and asylum-seekers within its territory — a testament to our shared humanity.

Refugees want opportunities, not handouts

  • For refugee youth, it is not just a matter of talent; it is a matter of prospects.
  • They want opportunities, not handouts.
  • They wish to be self-reliant and are eager to use their talents and passions to contribute to the communities hosting them.
  •  We can all do more to give them hope and those opportunities while they are away from home.

Dismantling the barriers

  • Refugees and asylum seekers encounter a myriad of obstacles, such as legal recognition and challenges in obtaining government-issued documents, which hinder their access to essential services, including financial support and health care.
  • It is incumbent upon us to dismantle these barriers and ensure that they are afforded equal opportunities in employment, education, housing, and health care.
  • Our efforts in creating an inclusive society must cater to the unique needs of refugee youth.
  • To ensure that truly no one is left behind, we should engage with and include youth, especially refugee youth, in the realisation of the Sustainable Development Agenda.
  • Addressing the rising number of the forcibly displaced is an urgent moral imperative that demands our collective action.
  • The Global Compact on Refugees acknowledges the magnitude of the displacement crisis and calls for solidarity through a whole of society approach.
  • It is built on the understanding that the responsibility towards the forcibly displaced is not limited to governments but extends to each one of us including individuals, the private sector, non-government organisations and community-based organisations.
  • It also recognises that the Global South is disproportionately affected and that host communities need assistance.


  • This is a critical moment in our lifetimes when we have the power to shape future generations. And we invite individuals, the private sector and governments to do their part in supporting youth from refugee and host communities. Together, we can truly ensure the Government of India’s vision of ‘Viksit Yuva Viksit Bharat’ is realised.


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