Can sound levitate objects and create holograms you can touch? with Sriram Subramanian

The talk is a compelling and accessible presentation of cutting-edge research in acoustic levitation and haptic holography. Professor Subramanian’s expertise is evident, and he effectively communicates complex concepts using analogies and live demonstrations. The scientific content is solid: he explains the physics of acoustic radiation forces, the Gor’kov potential, and the computational methods used to shape sound fields. The key insight that levitation can be achieved by a simple superposition of a focal point and a trap signature is presented clearly and is backed by the live demos. The demonstrations are impressive and serve to validate the theoretical claims. However, the talk is a public lecture, so it lacks detailed citations and rigorous quantitative analysis. The speaker does not delve into the limitations or potential risks of the technology, and the discussion of applications remains somewhat speculative. The audio issue mentioned in the description is noticeable but does not detract from the content. The title accurately reflects the content, and the talk successfully answers the question posed. Overall, this is a high-quality, informative presentation that balances technical depth with public engagement.

The title accurately reflects the content: the talk demonstrates acoustic levitation and haptic holograms, answering the question posed.

8/10

The speaker is a recognized expert (FREng, Chair in Emerging Technologies at UCL) and presents live demonstrations and computational methods. The content is based on peer-reviewed research, though the talk is a public lecture without detailed citations. The audio issue is acknowledged but does not affect the scientific content.

Markers derived by PSI from the transcript: the creator did not define chapters.

• 01:00Introduction to acoustic levitation with two transducers and standing waves.
• 03:00Demonstration of levitating various materials (coffee beans, milk, meat, lettuce).
• 05:00Explanation of the phased array of ultrasound speakers and phase control.
• 08:00Discussion of the Gor'kov potential and the objective function for levitation.
• 10:00Revelation that levitation can be simplified to focal point plus trap signature.
• 12:00Live demo of moving a levitated particle with a finger.
• 15:00Demonstration of haptic feedback and the sensation of sound on the palm.
• 18:00Video showing a levitating object that can be seen, felt, and heard simultaneously.
• 21:00Introduction to the inverse problem of creating arbitrary shapes from sound.
• 24:00Discussion of applications in human-computer interaction and life sciences.

• Members Exclusive Q&A — Continuation of the talk with audience questions.
• Ri Science Podcast — Podcast by the Royal Institution, possibly featuring related content.
• Editing Ri talks and moderating comments — Royal Institution page about editing talks and moderating comments.
• Donate to the Ri — Support page for the Royal Institution.

• Acoustic levitation on Wikipedia — General overview of acoustic levitation, consistent with the talk's content.
• Gor'kov potential on Wikipedia — Theoretical framework mentioned in the talk.