Google’s Quantum Echoes Experiment

• 13 Dec 2025

Source: TH

Why in News?

Google has achieved a breakthrough in quantum computing called Quantum Echoes marking a significant advancement in understanding quantum behavior and has revived global discussions on Q-day, encryption security, and the future of quantum-safe systems.

Summary

• The Quantum Echoes experiment advanced quantum physics by measuring information scrambling, separate from cryptographic code-breaking.
• It warns of the Q-Day threat and harvest-now-decrypt-later risk to current encrypted data.
• A large technology gap persists, driving global moves like NIST’s PQC standards and RBI advisories toward quantum-safe systems.

What is Google’s Quantum Echoes Experiment?

• About: It is a fundamental physics experiment run on Google's 65-qubit Willow quantum processor, designed to observe and measure how quantum information scrambles and refocuses within a complex, entangled system—a phenomenon metaphorically called an echo. 
  • Scientists used a tool called an Out-of-Time-Order Correlator (OTOC), which works like giving the quantum system a tiny push, reversing its evolution, and then detecting the returning echo.
• Q-Day Concept: Refers to when quantum computers become powerful enough to break public-key encryption. It would not instantly expose all secrets, but any encrypted data stored today could be decoded later if intercepted now — a risk known as “harvest now, decrypt later.
• Encryption Vulnerability: RSA-2048 (Rivest–Shamir–Adleman) encryption, which secures nearly all online communication, works by multiplying large prime numbers. 
  • Quantum computers using Shor's algorithm (a quantum method that factors large numbers efficiently) could potentially break this by finding prime factors exponentially faster than classical computers.
• Current Technology Gap: Breaking RSA-2048 encryption would require approximately 20 million physical qubits and 8 hours. Current processors like Google's Willow and IBM's Condor have only a few hundred noisy qubits. 
  • Fault-tolerant quantum computers needing millions of logical qubits remain 5–8 years away.
• Global Preparedness: US National Institute of Standards and Technology (NIST) has standardized post-quantum cryptography (PQC) algorithms — CRYSTALS-Kyber for encryption and Dilithium for digital signatures. 
  • Companies like Google and Cloudflare are adopting hybrid encryption.
• India's Response: Reserve Bank of India (RBI) is urging organizations to transition to quantum-safe systems before the end of the decade, though most networks remain unprotected.

Frequently Asked Questions (FAQs)

1. What is Google’s Quantum Echoes experiment?
It is a physics experiment on the 65-qubit Willow processor that measures how quantum information spreads and refocuses using OTOCs.

2. What is Q-day in cybersecurity?
Q-day is the point when quantum computers become powerful enough to break public-key encryption, raising the “harvest now, decrypt later” threat.

3. Why is RSA-2048 vulnerable to quantum computing?
Shor’s algorithm can factor large numbers exponentially faster using quantum superposition and entanglement, undermining RSA’s prime-factor security

UPSC Civil Services Examination Previous Year Question (PYQ) 

 Q. Which one of the following is the context in which the term "qubit" is mentioned?

(a) Cloud Services 

(b) Quantum Computing 

(c) Visible Light Communication Technologies 

(d) Wireless Communication Technologies 

Ans: (b)