We present a protocol to realize topological discrete-time quantum walks,which comprise a sequence of spindependent flipping displacement operations and quantum coin tossing operations,with a single trapped ion.It is ...We present a protocol to realize topological discrete-time quantum walks,which comprise a sequence of spindependent flipping displacement operations and quantum coin tossing operations,with a single trapped ion.It is demonstrated that the information of bulk topological invariants can be extracted by measuring the average projective phonon number when the walk takes place in coherent state space.Interestingly,the specific chiral symmetry owned by our discrete-time quantum walks simplifies the measuring process.Furthermore,we prove the robustness of such bulk topological invariants by introducing dynamical disorder and decoherence.Our work provides a simple method to measure bulk topological features in discrete-time quantum walks,which can be experimentally realized in the system of single trapped ions.展开更多
An optical phase locking method based on direct phase control is proposed.The core of this method is to synchronize the carrier by directly changing the phase of the local beam.The corresponding experimental device an...An optical phase locking method based on direct phase control is proposed.The core of this method is to synchronize the carrier by directly changing the phase of the local beam.The corresponding experimental device and the supporting algorithm were configured to verify the feasibility of this method.Phase locking can be completed without cycle skipping,and the acquisition time is 530 ns.Without an optical preamplifier,a sensitivity of-34.4 d Bm is obtained,and the bit error rate is 10^(-9) for 2.5 Gbit/s binary phase-shift keying modulation.The measured standard deviation of the phase error is 5.2805°.展开更多
This paper provides a concrete and simple introduction to two pillars of domain theory : (1) solving recursive domain equations, and (2) universal and saturated domains. Our exposition combines Larsen and Winskel'...This paper provides a concrete and simple introduction to two pillars of domain theory : (1) solving recursive domain equations, and (2) universal and saturated domains. Our exposition combines Larsen and Winskel's idea on solving domain equations using information systems with Girard's idea of stable domain theory in the form of coherence spacest or graphs. Detailed constructions are given for universal and even homogeneous objects in two categories of graphs: one representing binary complete, prime algebraic domains with complete primes covering the bottom; the other representing w-algebraic, prime algebraic lattices. The back- and-forth argument in model theory helps to enlighten the constructions.展开更多
基金Project supported by the National Key R&D Program of China(Grant No.2017YFA0304203)the National Natural National Science Foundation of China(Grant Nos.11604392 and 11674200)+1 种基金the Changjiang Scholars and Innovative Research Team in Universities of Ministry of Education of China(Grant No.IRT 17R70)the Fund for Shanxi“1331 Project”Key Subjects Construction,and the 111 Project,China(Grant No.D18001).
文摘We present a protocol to realize topological discrete-time quantum walks,which comprise a sequence of spindependent flipping displacement operations and quantum coin tossing operations,with a single trapped ion.It is demonstrated that the information of bulk topological invariants can be extracted by measuring the average projective phonon number when the walk takes place in coherent state space.Interestingly,the specific chiral symmetry owned by our discrete-time quantum walks simplifies the measuring process.Furthermore,we prove the robustness of such bulk topological invariants by introducing dynamical disorder and decoherence.Our work provides a simple method to measure bulk topological features in discrete-time quantum walks,which can be experimentally realized in the system of single trapped ions.
基金supported by the National Key R&D Program of China(No.2020YFB0408302)Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB43030400)+1 种基金National Natural Science Foundation of China(No.91938302)Key Project of Chinese Academy of Sciences(No.ZDRWKT-2019-1-01-0302)。
文摘An optical phase locking method based on direct phase control is proposed.The core of this method is to synchronize the carrier by directly changing the phase of the local beam.The corresponding experimental device and the supporting algorithm were configured to verify the feasibility of this method.Phase locking can be completed without cycle skipping,and the acquisition time is 530 ns.Without an optical preamplifier,a sensitivity of-34.4 d Bm is obtained,and the bit error rate is 10^(-9) for 2.5 Gbit/s binary phase-shift keying modulation.The measured standard deviation of the phase error is 5.2805°.
基金This work is supported by the National Natural Science Foundation of China (No.69873034), the Foundation forUniversity Key Tea
文摘This paper provides a concrete and simple introduction to two pillars of domain theory : (1) solving recursive domain equations, and (2) universal and saturated domains. Our exposition combines Larsen and Winskel's idea on solving domain equations using information systems with Girard's idea of stable domain theory in the form of coherence spacest or graphs. Detailed constructions are given for universal and even homogeneous objects in two categories of graphs: one representing binary complete, prime algebraic domains with complete primes covering the bottom; the other representing w-algebraic, prime algebraic lattices. The back- and-forth argument in model theory helps to enlighten the constructions.
