scholarly journals Effects of quantum error correction on entanglement sudden death

2014 ◽  
Vol 14 (1&2) ◽  
pp. 39-55
Author(s):  
Muhammed Yonac ◽  
Joseph H. Eberly
Keyword(s):  
Sudden Death ◽  
Error Correction ◽  
Quantum Coherence ◽  
Early Stage ◽  
Entanglement Sudden Death ◽  
Mixing Angle ◽  
Phase Damping ◽  
Pure Phase ◽  
Non Local ◽  
Quantum Error

We investigate the effects of error correction on non-local quantum coherence as a function of time, extending the study by Sainz and Bjork. We consider error correction of amplitude damping, pure phase damping and combinations of amplitude and phase damping as they affect both fidelity and quantum entanglement. Initial two-qubit entanglement is encoded in arbitrary real superpositions of both $\Phi$-type and $\Psi$-type Bell states. Our main focus is on the possibility of delay or prevention of ESD (early stage decoherence, or entanglement sudden death). We obtain the onset times for ESD as a function of the state-superposition mixing angle. Error correction affects entanglement and fidelity differently, and we exhibit initial entangled states for which error correction increases fidelity but decreases entanglement, and vice versa.

scholarly journals COMBATING ENTANGLEMENT SUDDEN DEATH WITH NON-LOCAL QUANTUM-ERROR CORRECTION

2009 ◽  
Vol 07 (supp01) ◽  
pp. 245-255 ◽  
Author(s):  
ISABEL SAINZ ◽  
GUNNAR BJÖRK
Keyword(s):  
Sudden Death ◽  
Error Correction ◽  
Finite Time ◽  
Quantum Error Correction ◽  
Entanglement Sudden Death ◽  
Local Quantum ◽  
Non Local ◽  
Quantum Error ◽  
Made In

We study the possibility of preventing finite-time disentanglement caused by dissipation by making use of non-local quantum error correction. This is made in comparison to previous results, where it was shown that local quantum error correction can delay disentanglement, but can also cause entanglement sudden death when it is not originally present.

scholarly journals Local available quantum correlations for Bell Diagonal states and Markovian decoherence

2018 ◽  
Vol 64 (6) ◽  
pp. 662
Author(s):  
Hermann L Albrecht Q ◽  
Douglas F. Mundarain ◽  
Mario I. Caicedo S.
Keyword(s):  
Sudden Death ◽  
Quantum Discord ◽  
Quantum Correlations ◽  
Entanglement Sudden Death ◽  
Dissipative Dynamics ◽  
Phase Damping ◽  
Werner States ◽  
Kraus Operators

Local available quantum correlations (LAQCs), as dened by Mundarain et al. [19], are analytically determined for Bell Diagonal states. Using the Kraus operators formalism [10], we analyze the dissipative dynamics of 2-qubit LAQCs under Markovian decoherence. This is done for Werner states under the depolarizing [20] and phase damping channels [21]. Since Werner states are among those that exhibit the so called entanglement sudden death [27], the results are compared with the ones obtained for Quantum Discord [22], as analyzed by Werlang et al. [24], as well as for entanglement, i.e. Concurrence[7]. The LAQCs quantier, as Quantum Discord does, only vanishes asymptotically.

scholarly journals Entanglement of Open Quantum Systems in Noninertial Frames

2012 ◽  
Vol 19 (02) ◽  
pp. 1250013 ◽  
Author(s):  
S. Khan ◽  
M. K. Khan
Keyword(s):  
Sudden Death ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Unruh Effect ◽  
Entanglement Sudden Death ◽  
Phase Damping ◽  
Amplitude Damping Channel ◽  
Stationary Frame ◽  
Depolarizing Channel ◽  
Accelerated Frames

We study the effects of decoherence on the entanglement generated by Unruh effect in accelerated frames by using various combinations of an amplitude damping channel, a phase damping channel and a depolarizing channel in the form of multilocal and collective environments. Using concurrence as entanglement quantifier, we show that the occurrence of entanglement sudden death (ESD) depends on different combinations of the channels. The ESD can be avoided under a particular configuration of the channels. We show that the channels can be used to distinguish between a moving and a stationary frame.

Evolution from entanglement to decoherence

2007 ◽  
Vol 7 (5&6) ◽  
pp. 459-468 ◽  
Author(s):  
T. Yu ◽  
J.H. Eberly
Keyword(s):  
Sudden Death ◽  
Time Evolution ◽  
Early Stage ◽  
Environmental Noise ◽  
Entanglement Sudden Death ◽  
Mixed States

We examine a class of bipartite mixed states which we call X states and report several analytic results related to the occurrence of early-stage decoherence or so-called entanglement sudden death (ESD) under time evolution in the presence of common types of environmental noise. Avoidance of sudden death by application of purely local operations is shown to be feasible in some cases.

scholarly journals A surface code quantum computer in silicon

2015 ◽  
Vol 1 (9) ◽  
pp. e1500707 ◽  
Author(s):  
Charles D. Hill ◽  
Eldad Peretz ◽  
Samuel J. Hile ◽  
Matthew G. House ◽  
Martin Fuechsle ◽  
...  
Keyword(s):  
Error Correction ◽  
Nuclear Spin ◽  
Quantum Coherence ◽  
Large Scale ◽  
Quantum Error Correction ◽  
Shared Control ◽  
Two Dimensional ◽  
Surface Code ◽  
Quantum Error ◽  
And Control

The exceptionally long quantum coherence times of phosphorus donor nuclear spin qubits in silicon, coupled with the proven scalability of silicon-based nano-electronics, make them attractive candidates for large-scale quantum computing. However, the high threshold of topological quantum error correction can only be captured in a two-dimensional array of qubits operating synchronously and in parallel—posing formidable fabrication and control challenges. We present an architecture that addresses these problems through a novel shared-control paradigm that is particularly suited to the natural uniformity of the phosphorus donor nuclear spin qubit states and electronic confinement. The architecture comprises a two-dimensional lattice of donor qubits sandwiched between two vertically separated control layers forming a mutually perpendicular crisscross gate array. Shared-control lines facilitate loading/unloading of single electrons to specific donors, thereby activating multiple qubits in parallel across the array on which the required operations for surface code quantum error correction are carried out by global spin control. The complexities of independent qubit control, wave function engineering, and ad hoc quantum interconnects are explicitly avoided. With many of the basic elements of fabrication and control based on demonstrated techniques and with simulated quantum operation below the surface code error threshold, the architecture represents a new pathway for large-scale quantum information processing in silicon and potentially in other qubit systems where uniformity can be exploited.

scholarly journals Reducing the impact of radioactivity on quantum circuits in a deep-underground facility

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
L. Cardani ◽  
F. Valenti ◽  
N. Casali ◽  
G. Catelani ◽  
T. Charpentier ◽  
...  
Keyword(s):  
Error Correction ◽  
Quantum Coherence ◽  
Quantum Information Processing ◽  
Cooper Pairs ◽  
Superconducting Circuits ◽  
Deep Underground ◽  
Current Error ◽  
Quantum Error ◽  
The Impact ◽  
Nonequilibrium Quasiparticles

AbstractAs quantum coherence times of superconducting circuits have increased from nanoseconds to hundreds of microseconds, they are currently one of the leading platforms for quantum information processing. However, coherence needs to further improve by orders of magnitude to reduce the prohibitive hardware overhead of current error correction schemes. Reaching this goal hinges on reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we show that environmental radioactivity is a significant source of nonequilibrium quasiparticles. Moreover, ionizing radiation introduces time-correlated quasiparticle bursts in resonators on the same chip, further complicating quantum error correction. Operating in a deep-underground lead-shielded cryostat decreases the quasiparticle burst rate by a factor thirty and reduces dissipation up to a factor four, showcasing the importance of radiation abatement in future solid-state quantum hardware.

Sign in / Sign up

Export Citation Format

Share Document