Quantum capacities of transducers

Abstract

High-performance quantum transducers, which faithfully convert quantum information between disparate physical carriers, are essential in quantum science and technology. Different figures of merit, including efficiency, bandwidth, and added noise, are typically used to characterize the transducers’ ability to transfer quantum information. Here we utilize quantum capacity, the highest achievable qubit communication rate through a channel, to define a single metric that unifies various criteria of a desirable transducer. Using the continuous-time quantum capacities of bosonic pure-loss channels as benchmarks, we investigate the optimal designs of generic quantum transduction schemes implemented by transmitting external signals through a coupled bosonic chain. With physical constraints on the maximal coupling rate $${g}_{\max }$$ g max , the highest continuous-time quantum capacity $${Q}^{\max }\approx 31.4{g}_{\max }$$ Q max ≈ 31.4 g max is achieved by transducers with a maximally flat conversion frequency response, analogous to Butterworth electric filters. We further investigate the effect of thermal noise on the performance of transducers.

Differences in the Effect of Water on Deep Eutectic Solvents Based on Choline Chloride/Lauric Acid and Choline Chloride/Myristic Acid: Molecular Dynamics Simulations at Three Different Temperatures

“…[38] Hydrophilic DESs that use long-chain fatty acids, quaternary amine salts, and terpenes as hydrogen bond donors can be used as extractant for aqueous samples due to their instability in water. [32] Thus, the investigations carried out on different species in the studied systems appeared in the arena, a good agreement with the results obtained from the analysis of previous sections.…”

“…In type III DESs containing quaternary salt, the halogen anion (Cl − ) forms a hydrogen bond with ligand Y, which reduces the Coulomb force between the anion and cation [32] and this is representative of excellent dissolution properties for donating protons or accept electrons to form H‐bonds [33] . Furthermore, the tendency for the formation of hydrogen bonds between OA of choline cation and Cl − anion/O2 atom of FAs (LUA, MRA) are decreased with increasing temperature in [Ch + ][Cl − ]+LUA/MRA system and these interactions with Cl − anions are rather that is related to the small size of HBD and subsequently, shorter distance between components [29]…”

Correlating the charge-transfer gap to the maximum transition temperature in Bi 2 Sr 2 Ca n -1 Cu n O 2 n +4+δ

“…Because the J eff between local Cu moments has been proposed to be responsible for the spin singlet pairing (31), J eff ~1/D 3 thus correlates the CTG and the Cooper pairing strength. For n = 1 and 2, only the OP is present, and the increase of J OP is consistent with that derived through STM ( 9) and inelastic photon scattering (32). For the whole range with 1 ≤ n ≤ 9, Fig.…”

Lattice plainification advances highly effective SnSe crystalline thermoelectrics

“…A superior average ZT (ZT ave ) in the operating temperature range is required to achieve high conversion efficiency. Numerous methods have been devised to enhance thermoelectric performance, including optimization of carrier concentration (8), manipulation of electronic band structure (9)(10)(11), engineering of full-scale microstructure (12)(13)(14), and decoupling of electron and phonon transports (15)(16)(17).…”