Chapter 1: Hawking's Legacy

Stephen Hawking has long stood as a symbol for those striving to pursue their passions, regardless of challenges. Despite facing significant physical obstacles, he consistently demonstrated that the potential of the human mind knows no limits. Throughout his remarkable career, he authored approximately 55 influential papers, each making significant contributions to the realm of physics. Even in his final days, his enthusiasm for the subject remained unwavering. His concluding work was entitled, ‘Black Hole Entropy and Soft Hair.’

The Final Paper: 'Black Hole Entropy and Soft Hair'

Hawking, along with his collaborators Sasha Haco, Malcolm J. Perry, and Andrew Strominger, completed this pivotal paper shortly before his passing on March 14, 2018. This final contribution addresses the Black hole information paradox, which raises questions about the fate of quantum information that appears to be lost when an object enters a black hole. The examination of black holes was a central theme in Hawking's extensive career.

To grasp the concepts presented in this paper, a fundamental understanding of String theory is necessary. This theory posits that during the study of a black hole, one can delineate a boundary near the horizon of an anti-de Sitter (AdS) black hole, allowing for the counting of states of objects contained within that region. However, a significant challenge remains: there is no definitive region to establish this boundary, leading to arbitrary adjustments in its placement. Essentially, it becomes a matter of quantifying the microstates of the black hole itself rather than those within the AdS.

In the realm of String theory, the key idea regarding entropy origins revolves around Diffeomorphisms, which play a crucial role in understanding black holes. The research detailed in this paper explores how these Diffeomorphisms act meaningfully on a black hole's horizon. The investigation began with Supertranslations, although this line of inquiry was later found insufficient for fully elucidating the information contained within a black hole.

Ultimately, the research concluded that the photons surrounding a black hole's event horizon are responsible for encoding entropy. This phenomenon, referred to as ‘Soft Hair,’ was highlighted by Malcolm J. Perry, who stated in an interview about the paper, “What this paper does is show that ‘soft hair’ can account for the entropy. It’s telling you that soft hair really is doing the right stuff.”

While this paper contributes to our understanding of the information contained within black holes, it should not be assumed to encompass all quantum information present. Perry further remarked, “We don’t know that Hawking entropy accounts for everything you could possibly throw at a black hole, so this is really a step along the way. We think it’s a pretty good step, but there is a lot more work to be done.”

Hawking dedicated his life to uncovering the mysteries of black holes, leading to groundbreaking insights such as ‘Hawking Radiation,’ which transformed our understanding of these cosmic phenomena. This final paper serves as a crucial milestone toward unraveling the nature of information in singularities, highlighting the ongoing journey in the field of physics.

Lecture on Hawking's Last Paper

In a lecture at the Institute for Advanced Study, one of the co-authors, Andrew Strominger, delves deeper into the findings of this significant work.

Further Exploration of Hawking's Theories

The second video, featuring Thomas Hertog discussing Hawking's final theory, provides additional insights into the implications of this groundbreaking work.

Contributed by Rishab Karki and curated by the author. Thank you for reading! If you found this article engaging, please support it by clicking the clap icon. To follow more of my work or support me further, consider becoming a Medium member through this link or buying me a coffee. Stay tuned for more insightful stories!