scholarly journals Unconditionally secure quantum bit commitment based on the uncertainty principle

Author(s):  
Guang Ping He

Unconditionally secure quantum bit commitment (QBC) was considered impossible. But the no-go proofs are based on the Hughston–Jozsa–Wootters (HJW) theorem (a.k.a. the Uhlmann theorem). Recently, it was found that in high-dimensional systems, there exist some states which can display a chaos effect in quantum steering, so that the attack strategy based on the HJW theorem has to require the capability of discriminating quantum states with very subtle difference, to the extent that is not allowed by the uncertainty principle. With the help of this finding, here we propose a simple QBC protocol which manages to evade the no-go proofs.

2013 ◽  
Vol 13 (1) ◽  
pp. 141-149 ◽  
Author(s):  
Yan-Bing Li ◽  
Qiao-Yan Wen ◽  
Zi-Chen Li ◽  
Su-Juan Qin ◽  
Ya-Tao Yang

Author(s):  
Frank S. Levin

The subject of Chapter 8 is the fundamental principles of quantum theory, the abstract extension of quantum mechanics. Two of the entities explored are kets and operators, with kets being representations of quantum states as well as a source of wave functions. The quantum box and quantum spin kets are specified, as are the quantum numbers that identify them. Operators are introduced and defined in part as the symbolic representations of observable quantities such as position, momentum and quantum spin. Eigenvalues and eigenkets are defined and discussed, with the former identified as the possible outcomes of a measurement. Bras, the counterpart to kets, are introduced as the means of forming probability amplitudes from kets. Products of operators are examined, as is their role underpinning Heisenberg’s Uncertainty Principle. A variety of symbol manipulations are presented. How measurements are believed to collapse linear superpositions to one term of the sum is explored.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Beatrice Da Lio ◽  
Daniele Cozzolino ◽  
Nicola Biagi ◽  
Yunhong Ding ◽  
Karsten Rottwitt ◽  
...  

AbstractQuantum key distribution (QKD) protocols based on high-dimensional quantum states have shown the route to increase the key rate generation while benefiting of enhanced error tolerance, thus overcoming the limitations of two-dimensional QKD protocols. Nonetheless, the reliable transmission through fiber links of high-dimensional quantum states remains an open challenge that must be addressed to boost their application. Here, we demonstrate the reliable transmission over a 2-km-long multicore fiber of path-encoded high-dimensional quantum states. Leveraging on a phase-locked loop system, a stable interferometric detection is guaranteed, allowing for low error rates and the generation of 6.3 Mbit/s of a secret key rate.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Huangjun Zhu

AbstractThe uncertainty principle imposes a fundamental limit on predicting the measurement outcomes of incompatible observables even if complete classical information of the system state is known. The situation is different if one can build a quantum memory entangled with the system. Zero uncertainty states (in contrast with minimum uncertainty states) are peculiar quantum states that can eliminate uncertainties of incompatible von Neumann observables once assisted by suitable measurements on the memory. Here we determine all zero uncertainty states of any given set of nondegenerate observables and determine the minimum entanglement required. It turns out all zero uncertainty states are maximally entangled in a generic case, and vice versa, even if these observables are only weakly incompatible. Our work establishes a simple and precise connection between zero uncertainty and maximum entanglement, which is of interest to foundational studies and practical applications, including quantum certification and verification.


2010 ◽  
Vol 81 (1) ◽  
Author(s):  
Loïck Magnin ◽  
Frédéric Magniez ◽  
Anthony Leverrier ◽  
Nicolas J. Cerf
Keyword(s):  

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6351
Author(s):  
Zishuai Zhou ◽  
Qisheng Guang ◽  
Chaohui Gao ◽  
Dong Jiang ◽  
Lijun Chen

We present an innovative method for quantum two-party cryptography. Our protocol introduces joint measurement and error estimation to improve the security of two-party cryptographic protocols. Our protocol removes the assumption of the attacker’s limited power and catches the attacking actions through highly estimated bit error rate. Our protocol is formally proved to be secure against both eavesdroppers and dishonest communication parties. We also utilize our designed protocol to construct two specific two-party cryptographic applications: Quantum bit commitment and quantum password identification.


JETP Letters ◽  
2001 ◽  
Vol 73 (2) ◽  
pp. 107-113
Author(s):  
S. N. Molotkov ◽  
S. S. Nazin
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document