2,634 research outputs found
Multiplexed control scheme for scalable quantum information processing with superconducting qubits
The advancement of scalable quantum information processing relies on the
accurate and parallel manipulation of a vast number of qubits, potentially
reaching into the millions. Superconducting qubits, traditionally controlled
through individual circuitry, currently face a formidable scalability challenge
due to the excessive use of wires. This challenge is nearing a critical point
where it might soon surpass the capacities of on-chip routing, I/O packaging,
testing platforms, and economically feasible solutions. Here we introduce a
multiplexed control scheme that efficiently utilizes shared control lines for
operating multiple qubits and couplers. By integrating quantum
hardware-software co-design, our approach utilizes advanced techniques like
frequency multiplexing and individual tuning. This enables simultaneous and
independent execution of single- and two-qubit gates with significantly
simplified wiring. This scheme has the potential to diminish the number of
control lines by one to two orders of magnitude in the near future, thereby
substantially enhancing the scalability of superconducting quantum processors
Distinguishing thermal histories of dark matter from structure formation
It is important to understand the implications of current observational
constraints and potential signatures on the thermal history of dark matter. In
this paper, we build the connection between the present-day velocities and the
production mechanism of dark matter and find that the current observation on
structure formation can be imposed to constrain the decoupling temperatures and
the phase-space distribution of dark matter. We further explore the potential
of distinguishing different possible thermal histories of dark matter with
hypothetical future observational data. Using the freeze-in/-out scenarios as
templates, we find that future precision data may uniquely identify the allowed
parameter spaces for freeze-in and freeze-out, or even completely rule out one
of the scenarios. This method can be more generally applied to other scenarios.Comment: 49 pages, 13 figures, 1 tabl
Density alteration in non-physiological cells
In the present study an important phenomenon of cells was discovered: the change of intracellular density in cell's response to drug and environmental factors. For convenience, this phenomenon is named as "density alteration in non-physiological cells" ( DANCE). DANCE was determined by discontinuous sucrose gradient centrifugation (DSGC), in which cells were separated into several bands. The number and position of the bands in DSGC varied with the change of cell culture conditions, drugs, and physical process, indicating that cell's response to these factors was associated with alteration of intracellular density. Our results showed that the bands of cells were molecularly different from each other, such as the expression of some mRNAs. For most cells tested, intracellular density usually decreased when the cells were in bad conditions, in presence of drugs, or undergoing pathological changes. However, unlike other tissue cells, brain cells showed increased intracellular density in 24 hrs after the animal death. In addition, DANCE was found to be related to drug resistance, with higher drug-resistance in cells of lower intracellular density. Further study found that DANCE also occurred in microorganisms including bacteria and fungus, suggesting that DANCE might be a sensitive and general response of cells to drugs and environmental change. The mechanisms for DANCE are not clear. Based on our study the following causes were hypothesized: change of metabolism mode, change of cell membrane function, and pathological change. DANCE could be important in medical and biological sciences. Study of DANCE might be helpful to the understanding of drug resistance, development of new drugs, separation of new subtypes from a cell population, forensic analysis, and importantly, discovery of new physiological or pathological properties of cells
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