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Using quantum nonlocality for device-independent confirmation of relativistic effects

Shubhayan Sarkar

TL;DR

This work first explains a simple attack that in principle can cause an arbitrary delay in the signal between sender and receiver, and proposes a way to overcome this problem by using a recently contrived idea of device-independent certification which utilises quantum nonlocality.

Abstract

Synchronizing clocks to measure time is a fundamental process underpinning every practical communication task from GPS to parallel computation. However, as the current protocols are based on classical communication between the sender and receiver, they are prone to simple attacks that could cause a slight delay in the signal which would then cause a massive error in further operations. In this work, we first explain a simple attack that in principle can cause an arbitrary delay in the signal between sender and receiver. We then propose a way to overcome this problem by using a recently contrived idea of device-independent certification which utilises quantum nonlocality. Consequently, clocks can be synchronized in a highly secure way without trusting any devices in the setup. We then extend this proposal to observe relativistic time dilation in a device-independent manner.

Using quantum nonlocality for device-independent confirmation of relativistic effects

TL;DR

This work first explains a simple attack that in principle can cause an arbitrary delay in the signal between sender and receiver, and proposes a way to overcome this problem by using a recently contrived idea of device-independent certification which utilises quantum nonlocality.

Abstract

Synchronizing clocks to measure time is a fundamental process underpinning every practical communication task from GPS to parallel computation. However, as the current protocols are based on classical communication between the sender and receiver, they are prone to simple attacks that could cause a slight delay in the signal which would then cause a massive error in further operations. In this work, we first explain a simple attack that in principle can cause an arbitrary delay in the signal between sender and receiver. We then propose a way to overcome this problem by using a recently contrived idea of device-independent certification which utilises quantum nonlocality. Consequently, clocks can be synchronized in a highly secure way without trusting any devices in the setup. We then extend this proposal to observe relativistic time dilation in a device-independent manner.
Paper Structure (1 section, 12 equations, 4 figures)

This paper contains 1 section, 12 equations, 4 figures.

Table of Contents

  1. Time relation between $S$ and $R$ when $S$ moves at a constant speed $v$

Figures (4)

  • Figure 1: A simplified GPS setup involves a satellite $S$ transmitting the time of signal dispatch and a receiver $R$ noting the time of reception. Using the time difference and the speed of light, $R$ calculates its distance from $S$.
  • Figure 2: Signal injection or time manipulation attack on the GPS signal: The time sent by the GPS is manipulated by the attacker Eve by delaying the signal or changing the time stamp.
  • Figure 3: DIQGPS: $S_0$ generates an entangled state sending one subsystem to the receiver $R$ and the other to satellite $S$. Both $R$ and $S$ perform two binary outcome measurements, with inputs $x,y=0,1$ and outcomes $r,s=0,1$, respectively (see bottom left). Additionally, $S$ and $R$ use clocks to record the times of their first two detections. $S$ encodes these times in the inputs of its subsequent measurements. Once the experiment is done, it sends all its data to $R$ and also reveals the rounds which were used to encode its time.
  • Figure 4: DIQGPS with $S$ moving at a constant velocity.