Physicists say it's possible to send messages to the past

Key Points:

• Physicists from MIT and Cornell have theoretically explored transmitting information backward in time using quantum simulations of closed timelike curves (CTCs), specifically post-selected CTCs (P-CTCs), without physically manipulating spacetime.
• Their research suggests that under certain conditions, sending information backward through a noisy quantum time loop could be more efficient than sending it forward, based on theoretical limits of information capacity.
• The study draws parallels to the sci-fi concept portrayed in the film Interstellar, where information is transmitted through a self-consistent time loop, avoiding typical time travel paradoxes by relying on memory and consistency of information.
• This work builds on Seth Lloyd’s earlier experiments with quantum entanglement that simulated time-loop behavior on a nanosecond scale, extending the analysis to noisy quantum communication channels.
• The authors stress that their findings are purely theoretical, with actual creation of CTCs far beyond current technological capabilities and involving complex issues related to causality and spacetime structure.