Details
Original language | English |
---|---|
Article number | 021006 |
Journal | Physical Review X |
Volume | 7 |
Issue number | 2 |
Publication status | Published - 10 Apr 2017 |
Externally published | Yes |
Abstract
Quantum randomness is an essential key to understanding the dynamics of complex many-body systems and also a powerful tool for quantum engineering. However, exact realizations of quantum randomness take an extremely long time and are infeasible in many-body systems, leading to the notion of quantum pseudorandomness, also known as unitary designs. Here, to explore microscopic dynamics of generating quantum pseudorandomness in many-body systems, we provide new efficient constructions of unitary designs and propose a design Hamiltonian, a random Hamiltonian of which dynamics always forms a unitary design after a threshold time. The new constructions are based on the alternate applications of random potentials in the generalized position and momentum spaces, and we provide explicit quantum circuits generating quantum pseudorandomness significantly more efficient than previous ones. We then provide a design Hamiltonian in disordered systems with periodically changing spin-glass-type interactions. The design Hamiltonian generates quantum pseudorandomness in a constant time even in the system composed of a large number of spins. We also point out the close relationship between the design Hamiltonian and quantum chaos.
Keywords
- Quantum information, Quantum physics, Statistical physics
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
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In: Physical Review X, Vol. 7, No. 2, 021006, 10.04.2017.
Research output: Contribution to journal › Review article › Research › peer review
}
TY - JOUR
T1 - Efficient quantum pseudorandomness with nearly time-independent hamiltonian dynamics
AU - Nakata, Yoshifumi
AU - Hirche, Christoph
AU - Koashi, Masato
AU - Winter, Andreas
PY - 2017/4/10
Y1 - 2017/4/10
N2 - Quantum randomness is an essential key to understanding the dynamics of complex many-body systems and also a powerful tool for quantum engineering. However, exact realizations of quantum randomness take an extremely long time and are infeasible in many-body systems, leading to the notion of quantum pseudorandomness, also known as unitary designs. Here, to explore microscopic dynamics of generating quantum pseudorandomness in many-body systems, we provide new efficient constructions of unitary designs and propose a design Hamiltonian, a random Hamiltonian of which dynamics always forms a unitary design after a threshold time. The new constructions are based on the alternate applications of random potentials in the generalized position and momentum spaces, and we provide explicit quantum circuits generating quantum pseudorandomness significantly more efficient than previous ones. We then provide a design Hamiltonian in disordered systems with periodically changing spin-glass-type interactions. The design Hamiltonian generates quantum pseudorandomness in a constant time even in the system composed of a large number of spins. We also point out the close relationship between the design Hamiltonian and quantum chaos.
AB - Quantum randomness is an essential key to understanding the dynamics of complex many-body systems and also a powerful tool for quantum engineering. However, exact realizations of quantum randomness take an extremely long time and are infeasible in many-body systems, leading to the notion of quantum pseudorandomness, also known as unitary designs. Here, to explore microscopic dynamics of generating quantum pseudorandomness in many-body systems, we provide new efficient constructions of unitary designs and propose a design Hamiltonian, a random Hamiltonian of which dynamics always forms a unitary design after a threshold time. The new constructions are based on the alternate applications of random potentials in the generalized position and momentum spaces, and we provide explicit quantum circuits generating quantum pseudorandomness significantly more efficient than previous ones. We then provide a design Hamiltonian in disordered systems with periodically changing spin-glass-type interactions. The design Hamiltonian generates quantum pseudorandomness in a constant time even in the system composed of a large number of spins. We also point out the close relationship between the design Hamiltonian and quantum chaos.
KW - Quantum information
KW - Quantum physics
KW - Statistical physics
UR - http://www.scopus.com/inward/record.url?scp=85021312671&partnerID=8YFLogxK
U2 - 10.1103/PhysRevX.7.021006
DO - 10.1103/PhysRevX.7.021006
M3 - Review article
AN - SCOPUS:85021312671
VL - 7
JO - Physical Review X
JF - Physical Review X
SN - 2160-3308
IS - 2
M1 - 021006
ER -